Incidents of mail theft have been “running rampant” in Los Altos in recent weeks, according to police. Dozens of victims have had mail stolen and checks for hundreds to thousands of dollars laundered. Others have had their identities stolen.

“We’ve seen a huge increase in theft of outgoing mail,” said Sgt. John Hughmanick. “It’s a spike that has picked up since late spring to the present. It appears that we are at one of the higher levels of this type of activity.”

The forgers steal the checks, treat them with chemicals that cause the ink to rise to the surface and then re-endorse the checks, he said.

Hughmanick warned that outgoing mail containing checks or bills should be taken to the post office or handed directly to a mail carrier. Putting checks in mailboxes is an invitation to check fraud or identity theft, he added.

“It’s a terrible inconvenience and it takes months and months to set things right,” he said.

The increase in mail theft is countywide and forgers have been targeting neighboring cities, including Los Altos Hills, Hughmanick said.