Police standoff with suspect ends in arrest in West Philadelphia.

WEST PHILADELPHIA (WPVI) -- A police standoff ended with an arrest Tuesday in West Philadelphia.

Police say 38-year-old Robert Thompson claimed to have an automatic weapon and to be holding his mother and grandmother hostage.

Just before 6:00 a.m. Tuesday, a 911 call came in reporting a person screaming on the 4700 block of Melon Street. Officers responded.

"A male came to the window," said Philadelphia Police Chief Inspector Joseph Sullivan. "He told (a police officer) to get off the property, threatened to shoot him, and also said that he was in possession of an AK-47."

Police went door-to-door evacuating residents in the neighborhood.

"They said it was a hostage situation, and we had to evacuate and leave the premises," Richburg said.

Students from nearby Parkway West High School were first told to shelter in place and then were evacuated. Some parents got calls from their children.

"She just said, 'They're moving us to another school. Come get us,'" said parent Martinis Garner. "I told her, 'I'm coming.'"

SWAT teams and the police department's homeland security unit were called in.

A hostage negotiator spoke with Thompson for about an hour before he surrendered without incident.

"We were just trying to keep him calm, to think about what's going on, which he did," said hostage negotiator John Geliebter.

There was no sign of a gun, but police were getting a warrant to search the house.

Thompson's brother rushed to the scene when he heard. He says his brother has a history of mental illness and doesn't own any guns.

"He's been under a lot of stress," said Kenneth Thompson. "He's a good person, graduated from St. Joseph's University. He's very intelligent, just going through a lot of problems right now."

Kenneth believes his brother would never hurt his mother and grandmother, both of whom are disabled. Neighbors tell us they have never known Robert to be violent.

"What you saw out here was a cry for help," said neighbor Don McCray.

"He needs to get evaluated for better help, evidently, from what happened this morning," said Kenneth Thompson.

The Philadelphia School District said that after the situation ended, the students who were evacuated were bused back to Parkway West High to complete the rest of the school day.