ELIZABETH -- An investigation has found that the Linden Police Department was deficient in disciplining Pedro Abad when the former officer was charged twice with DUI, before the double-fatal crash this March where he is also alleged to have been driving drunk, according to an announcement today from acting Union County Prosecutor Grace Park.

Park also announced that, in light of the investigation's findings, her office will now oversee the Linden Police Department's internal affairs division until further notice. The actions come after the completion of the Middlesex County Prosecutor's Office investigation of Abad's employment and discipline with the department, Park said.

Abad, 28, faces charges of aggravated vehicular homicide and manslaughter as part of a 27-count indictment stemming from the March 20 alleged drunk-driving crash, where authorities say he drove the wrong way on the West Shore Expressway in Staten Island and crashed head-on into a tractor-trailer, killing a fellow officer and a passenger in his car, and critically injuring another fellow officer.

In the days after the wrong-way crash, NJ Advance Media uncovered that Abad had been in eight crashes previously and was charged with drunk driving in two, one in Roselle in 2011 and the other in Rahway in 2013, which were a focus of the Middlesex County Prosecutor's Office investigation.

The investigation found no criminal conduct by authorities who handled Abad's two previous DUI charges, Park said, but did "highlight deficiencies" in how Abad was disciplined by the Linden Police Department's internal affairs division. The office would not specify the deficiencies.

In July, a lawyer for Linden Officer Patrik Kudlac, 24, who was critically injured in the wrong-way crash, filed a tort claim notice against the city over its handling of Abad's previous DUI charges.

The 2011 Roselle DUI charge against Abad occurred after he allegedly drove through the wall of a convenience store. That charge was later dropped because his attorney repeatedly failed to receive evidence from the Roselle Police Department, according to court records.

Abad pleaded guilty in the 2013 Rahway crash, where he struck a parked car and was caught on a police dashcam failing a sobriety test.

Park added that since May 2015, the Roselle Police Department under the leadership of Chief Gerard Orlando "established more comprehensive policies and procedures governing the preservation, retention, and transfer to appropriate prosecutors of certain forms of evidence in disorderly persons, motor vehicle, and criminal cases."

Park said Linden Police Chief James Schulhafer was notified in late December 2015 that, effective immediately and continuing until further notice, the oversight would include "a comprehensive review of all major disciplinary investigations, findings and penalties, as well as a regular review of all open internal affairs cases eligible for significant discipline, with intervention on any individual matter to occur on a case-by-case basis."

In a statement, Schulhafer said, "The Linden Police Department welcomes the additional oversight and is committed to doing everything we possibly can to improve our Internal Affairs function."

Linden Mayor Derek Armstead also said he welcomes the oversight.

"All anybody can really ask for is to have a better police force," Armstead said after receiving the news. "We should all be hoping for that. I think the prosecutor's office is hoping to help us have a better police department, and who can argue with that? In the wake of what has occurred, the additional oversight is definitely a good thing and it's welcome."

Park also announced a new initiative that requires all Union County police departments to notify the prosecutor's office "immediately upon receipt of information that any officer has any pending municipal court complaint involving a disorderly persons offense, petty disorderly persons offense, municipal ordinance violation, or driving while intoxicated charge."

"This review revealed that there is a clear need for our office to oversee the internal affairs functions of the Linden Police Department," Park said. "We believe that this will only help the department become stronger in its enforcement of professional standards. In addition, the implementation of the new countywide directive mandating notification will ensure that there is enhanced oversight, fairness and consistency over any issues that arise regarding our police officers."

A six-year veteran of the department, Abad earned a regular salary of $92,416 in 2014, according to public records.

After the fatal crash, where Abad was also critically injured, he remained on the force as an unpaid employee because he was unable to work and had used up his sick time. He was suspended in September when Staten Island authorities indicted him for the fatal crash. In early December, Linden police said he had recently been terminated from the police department, and that the dismissal was retroactive to Aug. 13, 2015. Police did not say why the termination was retroactive or exactly when he was terminated.

Abad's DUI charges in Roselle and Rahway were municipal offenses that occurred while he was off-duty and did not rise to a level that would automatically cost him his job, according to state statute. Experts told NJ Advance Media it falls to individual departments to determine how they move forward when one of their officers is arrested on or convicted of drunken driving charges.

Two passengers in Abad's Honda Civic - fellow Linden officer Frank Viggiano and Linden resident Joseph Rodriguez, both 28 - were killed in the crash.

Authorities said the men were driving home from Curves, a nearby strip club, and that Abad had a blood-alcohol level of .24, three-times the legal limit, at the time of the crash.

Abad's lawyer suggested at an October hearing that Abad may have been drugged by strippers at Curves before the crash and said an expert he hired "found some medical evidence that could be interpreted to mean Mr. Abad was drugged with GHB." At a December hearing, it was announced that Abad's blood will be tested for the drug. His next court hearing is scheduled for Jan. 25.

Abad's lawyer could not be immediately reached for comment on today's announcement.

Union County reporter Tom Haydon contributed to this story.

WRONG-WAY CRASH INDICTMENT

TIMELINE OF EVENTS

The timeline below takes you through facts uncovered and events since the March 20 crash. Move forward on the timeline by clicking the right side of each slide.

Jessica Remo may be reached at jremo@njadvancemedia.com. Follow her on Twitter @JessicaRemoNJ. Find NJ.com on Facebook.