Naiping Hou was last seen in Rancho Cucamonga, California, on March 16, 2025

A missing grandfather is feared to have been abducted from his California home as investigators have uncovered “suspicious” circumstances connected to his disappearance.

On Wednesday, April 22, the Federal Bureau of Investigation (FBI) announced in an X post that it has teamed up with the San Bernardino County Sheriff’s Department in the ongoing search for Naiping Hou.

Hou — a 74-year-old Asian man, weighing 170 pounds and 5 feet 7 inches tall — was last seen on March 16, 2025, in Rancho Cucamonga, according to the FBI’s missing person poster. He is described as having dark hair and eyes, as well as having a birthmark on his left upper shoulder.

The FBI’s involvement in his “suspicious disappearance” comes as authorities consider the possibility of foul play. Hou’s bank accounts were depleted before law enforcement officials were informed he’d vanished on May 4, 2025, KTLA reported, citing the San Bernardino County Sheriff’s Department.

Naiping Hou.FBI

Hou’s son, Wen Hou, recalled to KTLA last seeing his “very happy” father during a fishing trip in San Pedro in March.

He became concerned weeks later when he began to receive text messages that seemed out of character.

“[Always saying] he’s tired or he’ll call me later, just reasons that were strange,” Wen told KTLA. “He had very short responses and didn’t share photos anymore over the course of those couple of weeks.”

On Hou’s birthday on May 3, Wen began to consider that someone else may be using his father’s phone, as he refused to answer any calls and didn’t want to visit his grandchildren in Las Vegas, the LA Times reported.

Wen asked family friends to check on his father the following day. After entering Hou’s home, they found the property had been renovated with shoddy new paint on the interior, and all furniture had been removed.

Hou’s cars were also missing from the garage, according to the outlet.

Naiping Hou.findnaipinghou.com

“Something really strange has happened here,” Wen recalled to ABC 7. “There’s absolutely nothing in there; completely empty. Not even trash.”

“It’s unbelievable…the cars are gone; everything is gone,” he added.

Handprints were also seen on the garage door and the lawn was overgrown, with no sign of 74-year-old Hou.

Investigators believe someone used Hou’s cellphone to impersonate him for more than a month, having texted his wife not to return to their home of about 20 years, the LA Times reported. She received a text message saying that he would be joining her on her trip to China, where she was visiting family.

Naiping Hou.findnaipinghou.com

While reviewing Hou’s bank accounts on July 9, authorities discovered that “extensive fraudulent transactions” had been conducted around the time of his disappearance, per KTLA.

“There have been an excessive amount of fraudulent withdrawals from his bank account,” Mara Rodriguez, a spokesperson for the San Bernardino County Sheriff’s Department, told ABC 7. “We’re very concerned for his safety, and our main focus is to locate him and get him back with his family.”

More than $1 million has been withdrawn from Hou’s bank account since he was reported missing.

Naiping Hou.FBI

Wen, who is a hedge fund and cryptocurrency investor, doesn’t know who is potentially behind his father’s disappearance, but theorized to the LA Times that contractors who previously worked on his father’s home may have kidnapped him.

“Money was being wired out to buy gold online,” Wen told ABC 7, adding that his father’s accounts were also being used to purchase cryptocurrency. “He’s not an online-savvy person, so I don’t know how he’s able to buy gold online.”

Wen has created a website with photos and information regarding his father’s disappearance, while offering a $250,000 reward for information that could lead to safely locating him.

“The family is heartbroken, we just want him back,” said Wen in a video on the website.

A representative from the FBI and the San Bernardino County Sheriff’s Department did not immediately respond to PEOPLE’s request for further comment.