The committee searching for a new Prince George's County police cheif has narrowed its list to three candidates who represent generally different approaches to police issues.

One candidate is Robert L. Rabe, an assistant D.C. police chief who is noted for negotiating in hostage situations.

Another is E. Wilson Purdy, a controversial law enfocement officer recently fired as public safety director in Dade County, Fla., who is generally considered a conservative.

The third is Wesley A. Pomeroy, a longtime federal law enforcement Adminstration. He is considered liberal in his approach to police issues.

The five-member committee charged with finding a successor to outgoing chief John W. Rhoads held interview sessions last week and sent the three names on Friday to County Executive Lawrence J. Hogan.

Hogan could reject the proposed candidates, but sources close to the committee said he is expected to choose one of the three to replace Rhoads, who retires Friday on a disability pension.

Possibly the most controversial and conservatively oriented of the three candidates is Purdy, who was dismissed May 25 aftter serving for 13 years as public safety director in the county that includes Miami.

The dismissal followed a controversy over allegations of mistreatment of a man whose home was raided by mistake by officers in Purdy's agency.

The U.S. Commission on Civil Rights had criticized Purdy's agency in the past for alleged failure to hire women and minorities.

Pomeroy, a former White House aide on drug problems and a former special assistant to Attorney General Ramsey Clark i the Johnson administration, is DEA's liaison with the State Department. From 1974 to 1977, he was police chief of Beckeley, Calif.

Some souces suggested that the strongest candidate of the three may be Rabe, whose success in negotiating in hostage situations won him the sobriquet of "Golden Voice".

A 28-year veteran of the D.C. force, Rabe achieved his greatest prominence in March 1977 when he played a major role in the negotiations that ended a series of buildings take overs here by members of the Hanafi Muslim sect.

"He's a strict policeman who's paid his dues and has ties to the community," said one source, who noted that Rabe has lived in Prince George's for two decades.

Rabe, currently asssitant chief for inspectional services, declined last night to confirm that he is on the list of finalists.

However, he said that if offered the county post, he would take it.

Whoever gets the job wil command a force that has just passed through a tumultuous period marked by progress and problems in police-community relations, particularly in the area of the black-white relations.

Incidents during the last few years have at times exacerbated tension between the force, which is 90 percent white, and members of the county's growing black population.

Sensitive labor nogtiations are also expected next year.

The selection committee was named last month after Rhoads announced he would retire as a result of aggravated injuring to his back.

Chairman of the panel is former D.C. Police Chief Maurice J. Cullinane, who is widely believed to have influenced the recent selection of a new chief in Montgomery County. The new Montgomery chief is Bernard D. Crooke Jr., a former assistant chief on the D.C. force.

Other panel members are lawyer Jerry Kaplan, retired County Circuit Court Judge Ralph W. Powers, psychiatrist Dr. Frank Ochbert and banker Roy I. Dabney Jr. CAPTION: Picture 1, ROBERT L. RABE. . . assistant D.C. police chief; Picture 2, E. WILSON PURDY. . . possibly the most controversial. 1970 photo