There are no locked gates, security guards or menacing dogs shielding the home of billionaire Ernest Rady.

That meant there was nothing to stop a phony deliveryman from forcing his way into the house and keeping Rady, his wife and a housekeeper bound with duct tape for hours before making off with a few hundred dollars, police said Wednesday.

Investigators say the intruder specifically targeted Rady, a financier ranked No. 140 last year on Forbes magazine's list of the 400 richest Americans.

Rady, 69, wasn't home when the suspect arrived at the La Jolla residence Tuesday afternoon, said San Diego police Capt. Mary Cornicelli.

The intruder buzzed the intercom and asked for "Mrs. Rady" to sign some documents, Cornicelli said. After Rady's wife, Evelyn, and a housekeeper opened the door, the suspect pulled out a handgun and stun gun and forced his way in, police said.

The women were marched through the house at gunpoint as the robber demanded cash, then were taken to the master bedroom and bound with duct tape, Cornicelli said.

Less than two hours later, Rady arrived and was stunned and bound by the intruder.

The man left the house with less than $1,000 in cash about five hours after arriving, police said. The Radys freed themselves and called police; Ernest Rady was briefly hospitalized with minor injuries.

Police were searching for the man Wednesday. Rady declined to comment on the ordeal when reached by telephone.

Rady, a former part-owner of the San Diego Padres, made a $2.1 billion fortune by establishing Westcorp, one of the country's largest auto finance companies. It was sold to Wachovia Corp. in 2005 for $3.42 billion.

"People may think that because they're not high profile they don't need protection, but they're totally wrong," said Joseph LaSorsa, a security expert. "Anyone who does their homework can find out where high-net-worth people live."