Saying "Alexandria needs me," former mayor Charles E. Beatley Jr. announced yesterday he will challenge incumbent Frank E. Mann for office.

Beatley, 62, a retired airline pilot, served as mayor from 1967 to 1976. Since then, the city has become the focus of intensive local and federal probes into alleged illegal gambling and prostitution. Alexandria Commonwealth's Attorney William L. Cowhig was indicted Aug. 3 on charges of bribery and illegal gambling and has stepped aside while awaiting trial.

"I was called by several people in August," Beatley said yesterday. "They said, 'Chuck, come-on back. We need you.'

Mann, who announced last month that he will run for reelction, said yesterday that Beatley's decision came as no surprise to him. Mann defended his record, saying, "I'm as honest as the day is long."

Beatley said he "disagreed" with Mann's defense of Cowhig on television newcasts last summer and blamed the city's problems on "lack of communication" within the City Council.

"It's a subtle thing. I think Mann's style doesn't produce results. I think my style does," he said. "I think people know me as a person integrity. My style is free and easy, not closed."

Told of Beatley's remarks yesterday, Mann retorted, "What does style mean? Is this a fashion show? I couldn't care less what his style is."

Beatley also accused the city government of turning its back on some of Alexandria's recent troubles. "I think they thoght it would go away," he said.

Two weeks ago, according to City Councilman Donald C. Casey, Beatley met with the mayor and asked him not to run again.

"Beatley told Mann he [Beatley] would get everything cleaned up and then retired after one term," Casey said yesterday. "Mann's response was, 'If Chuck Beatley decides to run, he'll be dealth with politely and firmly.' That's a direct quote," Casey said, adding, "It's going to be an interesting campaign, I'll tell you that."

Beatley is expected to run unopposed in the Democratic primary next March. Mann is expected to run as an independent. According to Casey, "there won't be room for anyone else" when the ballots are cast in May.

Beatley lives in a log house in the west end of Alexandria and owns a farm in Warrenton in Fauquier County.

Mann, 58, a former state legislator who also served as mayor from 1961 to 1967, is a resident of Old Town.

Mann came under fire recently when he became embroiled in a dispute over nonpayment of taxes on a parcel of Alexandria waterfront property of which he is part-owner. He also has a reputation for abrasiveness, usually directed at long-winded council members.

Mann said yesterday he hadn't "the vaguest idea" what the campaign issues will be, and said there was no "cloud" over Alexandria's City Hall, as Beatley suggested yesterday.

"When I walked in" Mann said, "the sky was bright."

One issue that is sure to draw heated exchanges between the two candidates is the performance of City Manager Douglas Harman, who was hired by Beatley in 1975.

Several city officials have said privately that Mann is displeased with Harman and wants him replaced. Mann denied this yesterday, saying, "He's still here, isn't he?"

Beatley yesterday called the young city manager, "a bright and shining light."

Councilman Casey said he had written a letter to both Beatley and Mann last week, saying. "Get your noses out of Harman's business." Casey added, "I'll by angry if he is dragged into the campaign."

Both Beatley and Mann denied yesterday that Harman's performance would become an issue, but Casey said, "It sure looks that way."