Walnut Creek murder suspect arrested after standoff

The suspect involved in a 19-hour standoff after he allegedly fatally shot a woman he was dating was arrested Friday afternoon on suspicion of homicide, Walnut Creek police said.

Gregory Prokopowicz, 38, was arrested at 2:11 p.m. He was taken to the hospital to be treated for a minor injury to his ribs from the less-than-lethal sponge round, according to police.

After he is treated, he will be taken to the Martinez Detention Facility, police said. No one else was injured during the standoff, according to police.

Prokopowicz allegedly killed Roselyn Policarpio, 47, around 1:30 p.m. on Thursday in the 1900 block of First Avenue in Walnut Creek, police said.

After the shooting, Prokopowicz fled in a Chevrolet sedan, which he abandoned about a half-mile away on Lynvale Lane. Police K-9s tracked to him to a home, but by then he had left, according to police.

Around 7 p.m., Walnut Creek officers spotted Prokopowicz in Martinez riding in the passenger seat of a silver Mercedes and pulled the car over.

The Mercedes driver got out of the car and was detained, interviewed by officers and released.

Prokopowicz did not get out of the car. He put a gun to his head and said he was going to “harm himself,” police said.

At one point during the night, Prokopowicz accidentally fired a single shot from a handgun through the car’s windshield, but no one was struck by the bullet, according to police.

The Contra Costa County SWAT Team was in a standoff with Prokopowicz through the night and into the morning. Around 11:30 a.m., Central County SWAT took over, police said.

Negotiators spoke with Prokopowicz for about an hour and a half when he left the car to get a water bottle. SWAT operators told him to keep his hands up and surrender, but he grabbed the water bottle and turned to run back to the car, according to police.

The SWAT team fired a less-than-lethal sponge round at him, hitting him the right ribcage, police said. Prokopowicz got back in the vehicle and closed the door.

After about an hour and a half, negotiators convinced Prokopowicz to throw his firearm out the window and then a knife, however, he armed himself with another knife and refused to give it up or come out.

SWAT deployed three rounds of tear gas into the car and within seconds Prokopowicz got out of the vehicle and surrendered, according to police.

Anyone with information is asked to call the Walnut Creek Police Department at (925) 935-6400 or Detective Greg Leonard at (925) 256-3523.