Cambridge, Brockton and state police arrested a second suspect in Brockton Monday night in connection with the murder of Carl F. Loebig, a Harvard employee who was stabbed to death last week in his apartment, one block from the Freshman Union.

The suspect, Arthur W. Brown, a 20-year-old Dorchester resident, was arrested without incident at 10:30 p.m. Monday, Det. William Maher, a spokesman for Cambridge police said yesterday.

The police issued warrants Thursday for the arrest of Brown and another suspect, Kevin D. Roach, who was arrested early Friday morning.

Yesterday morning. Brown appeared before a judge in Middlesex District Court in East Cambridge, where he was charged with murder, Maher said.

Brown is being held without bail at the Suffolk county jail at the request of the Middlesex county judge who arraigned him, Robert Rufo, a Suffolk county sheriff, said yesterday. Brown was probably incarcerated in the Suffolk jail to prevent him from communicating with his co-defendant, Roach, who is being held without bail in Billerica Rufo added.

A friend of Loebig's and professor of philosophy at Boston University, Frank Coleman, has said that Loebig was trying to help Brown, whom Coleman described as an alcoholic. Coleman said Loebig met Brown while lifting weights at a gymnasium near Boston's so-called Combat Zone.

Brown is "very much a street person." Coleman said, adding that he met Brown at a performance of the opens "Aida," to which Loebig had brought Brown in an attempt to expose him to a better environment.

A prominent figure in the Boston arts community and editor of Arnoldia, the publication of the Arnold Arboretum, the 31-year-old Loebig was found stabbed to death last Thursday by the superintendent of his 84 Prescott St apartment.

A funeral service will be held Saturday at 12.30 p.m. at Our Lady of Victories Church on Arlington Blvd in Boston. The mass will be said by R. Phillip Leplante, pastor of the church, and by Fr. Eugene Merlet, president and founder of the Pro Musicis Foundation, of which Loebig was an active member