Investigators served a search warrant Monday at the home of an ex-boyfriend believed to have fathered the baby of a pregnant Parkland, Pierce County, woman missing more than a week.

Kassandra Cantrell, 33, hasn’t been seen or heard from since she left her family’s home the morning of Aug. 25.

She was reported missing Thursday by relatives who say she would never disappear, let alone skip her first ultrasound appointment.

On Monday, a Pierce County sheriff’s SWAT team served a search warrant at a South K Street home.

Cantrell’s ex-boyfriend lives there with his current girlfriend and was home at the time, authorities said.

“He is not in custody or detained at this point,” sheriff’s spokesperson Ed Troyer said.

The FBI’s forensic team conducted a search of the house, and was continuing to process the home Tuesday.

Cantrell’s cellphone hasn’t been used since the day she disappeared. It last pinged off a cell tower on Vashon Island, which prompted a two-day search for signs of Cantrell in Point Defiance Park.

Cantrell’s Mazda 3 sedan was found in the 300 block of 25th Street East near the Interstate 705 overpass in Tacoma on Friday evening with the keys inside.

Detectives are reviewing surveillance video from the area in hopes of figuring out who abandoned the vehicle there and when.

Cantrell is described as 5 feet 7 inches tall and 180 pounds, with brown hair and blue eyes.

Anyone with information about her whereabouts is asked to call 911.