WESTPORT — Another “check-washing” case — a $40 check stolen, changed and cashed for $8,000 — was reported this week by police, only a week after a warning was issued about a spike in such crimes.

In the latest incident, Francisco Jamie De La Rosa, 39, of Lynn, Mass., was charged Nov. 2 with second-degree identity theft and third-degree larceny.

Check washing occurs when a check is stolen and details such as the payee’s name or payment amount are erased — or “washed” — and replaced with fraudulent information. The check then is either cashed or deposited in a bank account controlled by the thief.

Checks targeted for the crime are most frequently stolen from either residential mailboxes or U.S. Postal Service mailboxes in town, police said in an earlier alert in February.

Investigation into the latest incident began Aug. 31 when a town resident filed a complaint with police, reporting that an envelope containing a $40 check was stolen from his mailbox.

The amount on the check subsequently was changed to $8,000, according to the police report, and the payee’s name altered to “Francisco Conrado Jamie.” The local man told police that he did not know anyone by that name.

The check was cashed at a Bank of America office, where the police detective investigating the case learned it had been deposited into an account opened by “Francisco Conrado Jamie De La Rosa.”

After gathering more evidence, a warrant for the arrest of De La Rosa, who turned himself in Nov. 2 at Police Department headquarters.

He was held on $40,000 bond and transported for arraignment later in the day at state Superior Court in Stamford.