The Whatcom County Sheriff's Office in northwest Washington said deputies received word Wednesday that Jenkins, who is Canadian, could be in the county. They found his car and an empty boat trailer at a marina in Blaine.
They had a report that a man matching his description arrived by boat at Point Roberts, U.S. territory about 10 miles away at the tip of a peninsula reachable by land only from Canada. Authorities believe Jenkins walked across the border to British Columbia.
After taping for the VH1 series finished, Jenkins met Fiore in Las Vegas casino in March and the two soon got married, said Fiore's mother, Lisa Lepore.
But in May, "they had a big blowout," Lepore said. "She had the marriage annulled."
At least one actor who appeared on "Millionaire" with Jenkins at a mansion in the Hollywood Hills was shocked by the latest developments and remembered a suave bachelor who grew in confidence as taping progressed.
Jenkins earned the nickname "Smooth Operator" because of "his cheeky cockiness. And I mean that in a friendly way," said Rob Locke, who played the host, a butler named Niles.
"We were all under the impression that he was single. Then I saw on Facebook that he got married and there were photos of him and his wife. My personal observation was, 'Wow, that was quick,"' Locke said, adding that taping ended in March.
Fiore's mother said her daughter and Jenkins had been fighting after a quickie Las Vegas wedding, and that he was jealous of her ex-boyfriends.
Court records show that Jenkins was charged in June in Clark County, Nev., with a misdemeanor count of "battery constituting domestic violence" for hitting Fiore in the arm and will be tried in December.
Jenkins also has a criminal history in his hometown of Calgary, Canada. He was sentenced to 15 months of probation in January 2007 on an unspecified assault charge, according to the Alberta, Canada Ministry of Justice. No further details were available.
Neal Tomlinson, a partner at the law firm representing Jenkins in the Nevada case, declined to comment and declined to say if his firm was representing Jenkins in the current matter.
Fiore was last seen alive with Jenkins at a poker game in San Diego. Jenkins reported her missing Saturday night to the Los Angeles County Sheriff's Department, police said.
It's still not clear how Fiore died, although a preliminary coroner's report indicated she was strangled.
Jenkins, variously described as an architect, real estate developer and investment banker from Calgary, appeared in three episodes of the series "Megan Wants a Millionaire," about a woman seeking to land a wealthy bachelor by putting suitors through their paces, such as designing a marketing campaign for her pet Chihuahua.
On the show, Jenkins was identified as an investment banker who had a couple million dollars.
A resume posted on the professional networking site LinkedIn.com says Jenkins graduated from Mount Royal College in Calgary in 1999, has a license to fly commercial airplanes and worked in investment sales and as president of a boutique development company focused on cutting-edge green technologies.
Fiore and Jenkins got married in Las Vegas on March 18, according to a Clark County marriage certificate.
It was a spontaneous marriage and by May, Fiore had the marriage annulled because "she didn't trust him because he was doing (things) behind her back," Lepore said. She declined to say what the incident involved.
Jenkins then went to Mexico to do another reality TV show, but struggled to get Fiore back when he returned. It was not immediately clear which show he appeared on.
"He convinced her during that month that he was really the guy for her," Lepore said. "He wrote poems and stories, and prayed, and (claimed he) had this huge spiritual awakening."
VH1 said in a statement Wednesday that it has postponed any future airings of the show. The statement also said that the show was an outside production licensed to VH1, but that it was produced and owned by 51 Minds Entertainment.
A message left at 51 Minds was not returned.
Associated Press writer Robert Jablon and Raquel Maria Dillon in Los Angeles, Ken Ritter in Las Vegas, Amy Taxin in Buena Park and Doug Esser in Seattle contributed to this report.