Officials now know the cause of death of a D.C. lawyer found dead in a stranger's car earlier this year near the U Street nightlife area.

Daniel Potucek died of an accidental MDMA overdose, a spokeswoman for the D.C. medical examiner said Friday. He was 34.

Potucek was found in the front passenger seat of a Mazda parked near 8th and U streets NW early the morning of Saturday, March 31 and declared dead shortly after.

Potucek lived in D.C.'s Petworth neighborhood and worked as a lawyer for the Transportation Security Administration. He previously attended Georgetown Preparatory School, Duke University and Harvard Law. He spoke seven languages. His mom said he often went to bars in the neighborhood where his body was found.

His mother previously told News4 her son's wallet, debit card, house keys and phone were gone — and he had no identification.

"I've been told that somebody put him in that car," Potucek's mother, Lorinda Potucek, said. She said she was told the car door had been unlocked.

Police were called about 7:40 a.m. March 31 and found a man showing no signs of life in the parked car.

One woman, who was nearby when police arrived and wished to remain anonymous when speaking to News4, described a disturbing scene: "I got here at 8 o'clock in the morning and the police just found the guy in the car. And they opened the car up and they said he fell out. And then they put the white sheet on him."

The car belonged to D.C. resident Alexander MacLennan, who parked his car before heading to a restaurant. After having a few drinks with his partner, MacLennan said he decided to go home and return for his car in the morning.

Overnight, the car became a death scene investigated by homicide detectives. When MacLennan tried to get his car, he found that the street had been blocked off. MacLennan left to run a few errands before returning.

But his car wasn't there.

"We just assumed it was stolen and having seen the police there earlier in the day, I just thought maybe, I don't know, something got smashed," he said.

He called police to report the vehicle stolen. A detective returned the call, asked a few questions and then broke the news: His car was part of a death investigation.

MacLennan said he didn't know Potucek and wasn't sure how he got into the car.

"We were definitely freaked out," he said.

Additional information on the circumstances of Potucek's death were not available immediately. News4 was unable to reach his family on Friday.

MDMA, also known as Ecstasy and Molly, can cause death in high doses. The drug can interfere with the body's ability to regulate temperature, which can lead to liver, kidney and cardiovascular system failure, according to the Drug Enforcement Administration.