Law enforcement authorities arrested a white, unemployed embalmer this morning in connection with two recent racially motivated bombings at Florida A&M University, a predominantly black institution here.

Lawrence Michael Lombardi Jr., 41, was taken into custody at his home here by a task force of federal, state and local law enforcement officers that has been investigating the pipe bomb explosions at Florida A&M on Aug. 31 and Sept. 22. After each bombing, the FBI said, local media received anonymous calls filled with racial slurs and threats of more violence.

Police were tipped off by callers who recognized Lombardi on a hardware store surveillance tape buying the kind of pipe used in the blasts, the FBI said. Local news media had shown an image of the man in the video at the request of police.

Lombardi, legs shackled, pleaded not guilty in federal court this afternoon to two charges of making an unregistered weapon. He was denied bond. Prosecutors said they expect to file additional charges against him, possibly including civil rights violations.

Lombardi's attorney, R. Tim Jansen, told the Associated Press: "He is absolutely innocent."

Though the blasts caused no injuries, they created tension and concern at one of the nation's oldest black universities. Scores of police searched campus buildings each morning, and the state installed surveillance cameras on the campus to increase security for the 12,000 students.

At a noontime news conference on the steps of the building where the first blast occurred, university President Frederick S. Humphries announced the bombing suspect's arrest and thanked the hundreds of students, faculty members and parents who came for Parents' Weekend for their perseverance.

"You have been the real heroes in this crisis," Humphries said. "It took courage to stay here on campus and carry out your normal activities.

"Each student enrolled in Florida A&M University came here to pursue a degree," he said. "Somewhere along this journey we've stumbled across a moment where a significant life lesson is being taught about the times in which we live."

Lombardi, who holds an active embalmer's license, worked for a funeral home until about a year ago, authorities said. He is married and has two children. Authorities would not say whether he has any ties with hate groups or whether he was acting alone, but the prosecutors indicated that the campus is now safe from the bombing threats.

Lombardi had access to the campus because he formerly worked for a company that had a contract with the university repairing vending machines. He kept his campus pass, officials said.

The university's student government president, Cornelius Minor, 21, a senior from Jonesboro, Ga., said he and other students are relieved that "this particular event is seeing some resolution."

"But bombs don't threaten us as much as the silent things, like [people] not wanting us to succeed."

Authorities said a caller had threatened another attack today, the start of Parents' Weekend, which brought thousands more people to the school. Some on campus today said they probably are more worried about campus safety than their children are.

"Our son was fairly rigidly determined to stay as long as he felt comfortable," said Kenneth McDowell, a Cincinnati physician, who arrived with his wife, Linda, Thursday night to see their son, Justin, 18, a freshman. "We acquiesced to his desires."

He added that the bombings were "a dastardly act, reprehensible."

"Our society is fraught with this kind of behavior," he said, "and the campus is a microcosm of society."

Research editor Margot Williams contributed to this report.