FEDERAL prosecutors yesterday charged a former Philadelphia School District police officer with allegedly impersonating a federal agent during a traffic stop on Interstate 95 and again at the fatal crash site of Amtrak Train No. 188 in May.

Michael Alvaro, 37, of Frankford, allegedly entered the Amtrak crash scene May 12 by posing as an agent with the Drug Enforcement Administration, according to an indictment presented yesterday in U.S. District Court in Philadelphia.

Court documents say that Alvaro spoke with a dispatcher less than 10 minutes after the crash, requested information and identified himself as "Sgt. Alvaro, DEA."

Alvaro, wearing a vest that said "POLICE," allegedly identified himself as an agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives when he met a detective and sergeant with the Philadelphia Police's Bomb Disposal Unit at the crater left by one of the overturned train cars.

And when the detective needed to leave the crater to track down some Amtrak officials, he left Alvaro in charge to make sure no one else entered in the crater, court documents allege. The detective returned to the crater later that night and Alvaro was gone, the documents say.

A source close to the investigation confirmed that Alvaro is a former officer with the school district. His indictment says he's never been involved with the DEA or the ATF.

Alvaro's time on the school district's police force was documented by a Daily News story on March 9, 2009:

The former Air Force police officer and 1996 Abraham Lincoln High School graduate was lauded for breaking up an attempted knifepoint robbery of three Central High School students just blocks from the school entrance on Feb. 25, 2009.

Alvaro was sitting in his school police SUV when he witnessed a teen brandishing the knife at the students. He dashed after the 15-year-old assailant, cuffing him after a brief scuffle, where the knife cut into the cop's bulletproof vest.

That incident, 10 days after and just one block away from where Philadelphia Police Officer John Pawlowski was gunned down, led Alvaro to advocate that school police officers be allowed to carry guns on the job.

"This is the perfect time - all these cops are getting killed for no reason," he told the People Paper. "It's just a matter of time before one of us gets it. We're all in the same boat. I go to every funeral. All I'm asking for is for them to train us, equip us and protect us."

Alvaro also is believed to have impersonated a DEA agent in November 2014, when he helped a Pennsylvania State Trooper during a DUI-related traffic stop on I-95.

The trooper realized that there was a warrant out for the driver and he asked Alvaro to keep watch while he ran some paperwork on the driver.

Alvaro then recommended conducting a search of the vehicle, fetching a crowbar from a tow truck there to tow the driver's car.

He pried open a spot in the trunk and found a "brick-shaped sludgy object" and claimed it was heroin. Later tests showed it to be paintballs.

Prosecutors say Alvaro could face up to 29 years in prison with three years of supervised release.

A call to a number listed as Alvaro's wasn't returned yesterday. His attorney, Kevin Harden, declined to comment.

On Twitter: @JBrandt_TU