The Middlesex County Superior Court is expected to hand down its decision today on a former Harvard police officer accused of larceny last December.

The prosecution accused Richard D. O'Connor of stealing over $100 worth of goods from a car in the Broadway St. garage while he was on duty on Dec. 15, 1978. The University placed him on suspension on Dec. 18, 1978, and fired him nine days later.

The 3rd District Court in Middlesex County found O'Connor guilty in February O'Connor appealed the case last May, and the trial resulted in a hung jury.

Sources said yesterday that Saul L. Chafin, chief of the University police, has promised the Harvard Police Association--the union for University police--that if the jury finds O'Connor innocent, the University will rehire him and give him back pay.

Chafin said earlier this week he will not comment until the verdict is announced.

However, Edward S. Powers, associate general counsel for Employee Relations, said yesterday he has "no idea" whether O'Connor would be rehired, regardless of the verdict.

"He'd have to apply and everything--he is no longer a Harvard employee," Powers said, adding, "I can't comment on an individual case like that."

The HPA will definitely take action if the jury finds O'Connor innocent and Harvard does not rehire him, sources said yesterday.

"We believe he was found guilty before being proven innocent," a source said, adding "It was an easy way to get rid of an officer--he got the shaft."

A man who says he witnessed the crime testified this week he saw an individual break into a white Vega, removing a tool box, 60 feet of white nylon sailing rope, a small packet resembling a wallet, and several other small objects, sources said yesterday.

Sources said Peter H. Aschaffenburg, the owner of the Vega and a freshman proctor in Stoughton, testified that several quarts of oil were missing from his car. However, Aschaffenburg had failed to introduce this evidence in earlier trials, sources added.

Aschaffenburg said yesterday he will not comment until the verdict is in.

Harvard police officers said yesterday they believe O'Connor is innocent of the charges. "We don't believe he would stoop so low as to do something like this--He's got six children," a source said.

O'Connor was fired from the police department last December after a routine hearing and an internal investigation. He had worked for the University for nine years with no previous suspensions.

O'Connor said earlier this week he will not comment until the trial is over