A business associate of a popular practitioner of Chinese herbal medicine has been arrested in connection with what California authorities say was the horrific slaying of the herbalist, his wife and the couple's 5-year-old daughter.

Pierre Haobsh, 27, of Oceanside, was taken into custody at gunpoint at a gas station in San Diego County, Santa Barbara County Sheriff Bob Brown said.

Investigators with an arrest warrant had been following a red Lexus that belonged to him, Brown said. A loaded gun and property belonging to one of the victims was found inside the car, the sheriff said.

Deputies who went to check on the welfare of 57-year-old Weidong "Henry" Han on Wednesday found the bodies of the physician, his 29-year-old wife, Hui jie "Jenni" Yu, and the couple's daughter Emily at the family's multimillion-dollar home on the outskirts of Santa Barbara.

Their bodies were found shot, wrapped in plastic and duct-taped in the garage, a sheriff's statement said. They had last been seen on Thursday, the night before they were found.

Brown said investigators were still trying to determine why the family was killed, but they believe Haobsh was recently involved in a business deal with Han and financial gain could have been involved.

"This investigation is far from over," Brown said. "It is complex and ongoing."

Two business associates of Han went to his home after he failed to show up for a meeting - something they told the authorities was highly uncharacteristic of him. The associates called authorities when they found the front door open and the family's cars parked outside.

The authorities did not say what led them from the palatial two-story home that sits on 2.8 hectares surrounded by avocado trees to the Oceanside area - where Haobsh was arrested - more than 270 kilometers to the south.

Haobsh is a US citizen, the authorities said, but few other details about him were released.

The killings shocked Santa Barbara, where Han, who owned and operated the Santa Barbara Herb Clinic, was a popular figure.

The couple's daughter was a kindergarten student at Foothill Elementary School, where counselors were made available to her classmates.

Han had owned and operated the Santa Barbara Herb Clinic since 1991, according to the clinic's website. Public records show he was a licensed acupuncturist.

A biography on his website says he earned degrees in Oriental and Western medicine from a Beijing university in 1982, graduating at the top of his class.