Prince George's County State's Attorney Arthur A. Marshall decided yesterday not to file charges against his assistant, Joseph C. Sauerwein, who was involved in two hit-and-run accidents last April. Instead, Marshall fined the deputy prosecutor $500.

Marshall had said earlier this week that the "proper thing to do under the circumstances would be to prosecute [Sauerwein] and allow him to defend himself." Yesterday, however, the state's attorney said he did not want to overrule the decision of the police officer who decided originally not to charge Sauerwein.

In explaining his decision not to charge Sauerwein, Marshall noted that his deputy had paid the owners of the two vehicles damaged in the April 26 hit-and-run accidents, had apologized for his conduct and had "learned a lesson."

Another factor in his decision, Marshall said, was that the owners of the two vehicles told police investigators that they did not want charges to be pressed against the deputy prosecutor.

But yesterday, Thomas Hudson, the owner of a pickup truck Sauerwein sideswiped on the Capital Beltway that April night, said he wanted county officials to press charges. "I think they should [bring charges against Sauerwein]," said Hudson. "I wouldn't want to be the one to do it, but I think they should, knowing what they know."

Sauerwein could not be reached for comment yesterday. His attorney, Edward P. Camus, said that "the fine would be paid promptly so that we can get this over and done with and go on to other things.

"Mr. Marshall had decided that it's resolved as far as he's concerned, and so it's over as far as we're concerned," Camus said.

Marshall repeated his earlier conclusion that Sauerwein also was responsible for ramming a parked car on Allentown Road during the same driving spree. However, Marshall said, police did not have enough evidence to prove that Sauerwein was behind the wheel when that accident occurred.

Acting Prince George's County Police Chief Joseph Vasco confirmed yesterday that police investigating the two accidents, following a report in The Washington Post, had not interviewed Sauerwein or the passenger in his car, Ronald H. Cooper, an administrative assistant in the state's attorney's office.

Vasco said Sauerwein and Cooper both had refused to speak to the police. "What are we supposed to do, beat him?" Vasco said of Cooper.

Vasco said the police investigation concluded that Sauerwein had not attempted to use his influence to persuade police not to charge him. He said an investigation was still under way as to why police separately investigating the two hit-and-runs never coordinated their probes.

Marshall also said that they county police officer William Brooks, who investigated the first incident, had told investigators he had never spoken to Sauerwein after the accident. Brooks originally told reporters that he had called Sauerwein at home and that Sauerwein had denied being the driver.

Officer Brooks refused comment yesterday. His attorney, Sam Serio, said Brooks told investigators that he had never spoken to Sauerwein, but that "if a witness can put Sauerwein behind the wheel, or Sauerwein wants to confess, then [Brooks] would charge him."

Marshall said that with the addition of the $500 administrative fine, Sauerwein had spent almost $5,000 as a result of the two hit-and-run accidents. The maximun fine that could have been levied against Sauerwein, Marshall said, was $500.

A statement released yesterday by the procecutor's office said that Marshall "apologized publicly for the actions of the deputy state's attorney for Prince George's County and believes that this experience will benefit all members of his office, and, hopefully, this will restore confidence in the Office of the State's Attorney and the legal profession."