An Allegheny County sheriff’s deputy who stopped an erratic driver in Whitehall on Wednesday discovered the naked body of a woman in the back seat of the van.

The woman, 32-year-old Ashley Morgenstern of Pittsburgh was blue and cold to the touch and was pronounced dead at the scene, Chief Deputy Kevin Kraus said Thursday.

The driver, Joseph Sokolowski, 26, of Whitehall was arrested and charged with possession of heroin, abuse of a corpse and driving under the influence.

The incident began when a bystander flagged down the deputy around 3:50 p.m. and told him about a van that was driving erratically on Baptist Road, Chief Deputy Kraus said.

The deputy found the vehicle at an intersection on Baptist Road and followed it as the driver made a left turn onto Plymouth Drive, a dead-end street.

Mr. Sokolowski stopped the van in the middle of the street. The deputy approached and found him to be disoriented and apparently under the influence of opioids, Chief Deputy Kraus said. Mr. Sokolowski’s speech was slurred, according to a criminal complaint. He denied using narcotics and told the deputy he was just hot and tired.

The van’s windows were tinted and covered with blinds so the deputy asked Mr. Sokolowski if anyone else was inside, according to the complaint.

Mr. Sokolowski hesitated, then said, “My girlfriend may be in the back,” according to the complaint.

The deputy then peeked behind Mr. Sokolowski and saw the naked body of a woman laying across the third row seat, Chief Deputy Kraus said.

He attempted to revive Ms. Morgenstern but was unsuccessful.

Mr. Sokolowski, who was fully clothed, said he’d woken up to find Ms. Morgenstern unresponsive, then he became scared and drove around for several hours, according to a criminal complaint. It’s not clear whether he woke up in the van or moved Ms. Morgenstern into the van before driving around.

A family member of Ms. Morgenstern’s declined to comment when reached by phone on Thursday.

Chief Deputy Kraus said the deputy who followed the van did everything he was supposed to do, and praised the woman who reported the van’s erratic driving.

“It’s just another tragic example of the opioid epidemic we’re facing in this country,” Chief Deputy Kraus said. “It’s almost impossible to control.”

Officers found two empty stamp bags in Mr. Sokolowski’s pant’s pocket, according to the criminal complaint.

Correction: This story was updated July 24, 2017 to reflect Joseph Sokolowski’s correct age. An earlier version misstated his age.

First Published: July 20, 2017, 3:23 p.m.
Updated: July 20, 2017, 6:01 p.m.