LOWELL — Defense attorneys in the Phan murder retrial are seeking an evidentiary hearing into what they describe as a State Police cover‑up surrounding a fatal 2023 crash in which Sgt. Scott Quigley — a key investigator in the case — was allegedly intoxicated and driving nearly twice the speed limit.

The filings, submitted in Middlesex Superior Court on Friday, ask to subpoena 19 current and former law‑enforcement officials — including Quigley — to testify under oath about how the Woburn crash was handled and when key information was disclosed.

According to the motion, filed by attorney Mark Wester for Billy Phan, Lorenzo Perez for Billoeum Phan, and William Dolan for Channa Phan, discovery materials show that at about 5 p.m. Dec. 12, 2023, Quigley was traveling 59 mph in a 30-mph zone in an unmarked cruiser on Lexington Street when he crossed into oncoming traffic and struck a handicapped-accessible van carrying 37-year-old Angelo Schettino, a disabled paraplegic who died a month later from his injuries.

Quigley has not been charged in the case.

A report from the Disabled Persons Protection Commission states Schettino was riding in a wheelchair inside the van, operated by the nonprofit Bridgewell Inc., and was returning from a medical appointment when the head-on crash occurred.

Quigley was taken to Lahey Hospital in Burlington with serious injuries. Medical records turned over in discovery documented Quigley’s blood alcohol concentration at 0.114. The motion further notes that upon arrival, Quigley — a former Woburn police officer — told hospital staff he was suffering from “lack of sleep” and had been “at the scene of an infant death” earlier that day.

Despite the severity of the crash, the defense argues, State Police investigators waited eight days to interview Quigley, never sought his toxicology results and issued only a marked‑lanes citation.

Records show the State Police had Quigley’s toxicology results by March 2024, but the information was not disclosed in the Phan case until jury selection in January — a delay that prompted Judge Chris Barry-Smith to ask during a Feb. 9 hearing, “who knew what when?”

The 19 witnesses who the defense seeks to call include Woburn police officers who first responded to the crash, State Police supervisors and prosecutors, including former Middlesex Assistant District Attorney Daniel Harren, who was the lead prosecutor during the first Phan trial, and current ADA Thomas Brant, who is part of the current prosecution team.

A key witness on the list is State Police Lt. Jennifer Penton, the crash investigator who the motion states did not interview Quigley until eight days after the collision and did not obtain his toxicology results.

The filing states Penton must establish whether she examined evidence from Quigley’s cruiser that would determine his speed — reportedly 59 mph in a 30-mph zone, according to vehicle records — why she failed to seek his toxicology results from Lahey Hospital, why she issued only a warning citation for a marked‑lanes violation despite serious injuries to all three people involved in the crash, why she waited to speak with Quigley, and why she did not interview the Woburn officers Quigley claimed to have interacted with at the scene.

The motion also cites a report Penton wrote in support of Quigley’s State Police Notice of Injury claim, in which she wrote that Quigley told her he had responded to an infant‑death call earlier that day, had been unable to sleep, and had fielded multiple follow‑up calls — concluding that he was injured “through no fault of his own and in the performance of his duties.”

In a footnote, the motion makes note that Penton was indicted on Feb. 6 by a Worcester grand jury on charges of involuntary manslaughter, causing serious bodily injury to a participant in a physical training program, and perjury, in connection with the 2024 death of State Police recruit Enrique Delgado-Garcia at the State Police Training Academy in New Braintree.

Penton has since been relieved of duty and had her certification suspended.

The filings also seek testimony from Trooper Mark Delaney, who — like Quigley — was assigned to the Middlesex District Attorney’s Office in the Phan case — and Trooper Martin Cooke.

Cooke’s body-worn camera captured him speaking with a supervisor while en route to the crash scene. According to the motion, Cooke offered to go to Lahey Hospital after learning Quigley had been taken there, but a supervisor told him not to, stating, “You don’t have to go to Lahey, Trooper Mark Delaney just called me and told me he is OK.”

The defense argues Cooke’s testimony is necessary to determine who gave that instruction and how Delaney learned of the collision so quickly. They also contend the crash should have been referred to an outside agency because it involved a State Police sergeant and was investigated by members of his own department.

The motion further highlights conflicting accounts within the State Police about what Quigley told supervisors regarding alcohol consumption. Letters exchanged describe him as having admitted drinking, denied drinking, or claimed confusion about the accuracy of his medical records.

Defense attorneys said the inconsistencies reinforce their argument that testimony under oath is necessary to determine who knew what when.

Quigley played a central role in the 2020 investigation into the shooting death of 22‑year‑old Tyrone Phet, of Lowell — allegedly committed by the Phan brothers — reviewing surveillance footage, analyzing cell‑phone data, and participating in witness interviews.

According to the motion, Quigley was involved in the recovery of a red 2014 Honda Pilot from Worcester that the Commonwealth alleges was used in the Phan brothers’ plan to shoot Phet and was sold shortly after the killing.

He reviewed cell‑phone records and GPS data from the vehicle of Abdulai Maranda — the Commonwealth’s immunized witness — and tracked Maranda’s movements on the night of Sept. 14, 2020.

Quigley was present for two days of interviews with Maranda and his attorney on Oct. 28 and Oct. 29, 2020, alongside Harren, and other investigators. The first day’s interview lasted seven to eight hours, the motion states, and the second concluded with Maranda’ grand‑jury testimony.

The motion states Quigley took no notes and wrote no report about the interviews, in violation of State Police policies and procedures, and that the interviews were not recorded. Quigley was also involved in the planning and strategy surrounding the arrests of the Phan brothers and directly located and arrested Billoeum Phan in Manchester, New Hampshire, on Oct. 30, 2020.

Defense attorneys argue that the handling of Quigley’s crash — and the timing of the disclosures — raises questions about whether the Middlesex District Attorney’s Office met its obligation to turn over information bearing on his credibility.

If granted, the evidentiary hearing would be the first time the underlying records and witness accounts surrounding the crash are examined under oath.

“Was the unit, many of whom are witnesses in our case, responsible for investigating homicides in the state of Massachusetts complicit, actively covering up the involuntary homicide committed by one of its own, who is also a key witness in this case?” Perez said following the Feb. 9 hearing.

Barry‑Smith has ordered the Middlesex District Attorney’s Office to respond to the defense filings by Friday.

In the meantime, Schettino’s family has filed a civil lawsuit against the State Police, alleging negligence in connection with the crash.

Quigley was suspended without pay earlier this month, and his case has been referred to the Suffolk District Attorney’s Office for possible criminal charges.

The Phan defense team has separately moved to dismiss the charges against the three brothers, arguing that the handling of the crash and the delayed disclosures irreparably undermine the integrity of the prosecution.

Follow Aaron Curtis on X @aselahcurtis, or on Bluesky @aaronscurtis.bsky.social.