Updated

An Indiana doctor was arrested Monday in connection with the unsolved killings of four people, including an 11-year-old boy, who all had ties to the Nebraska medical school he had attended before being fired.

Omaha authorities say 40-year-old Dr. Anthony Garcia is suspected in the May deaths of Creighton University professor Roger Brumback and his wife, Mary, as well as the 2008 stabbing deaths of 11-year-old Thomas Hunter and his family housekeeper, Shirlee Sherman.

Roger Brumback and Thomas Hunter's father worked in Creighton's medical school pathology department and the men had fired Garcia for erratic behavior in 2001, when he was a pathology resident, Omaha Police Chief Todd Schmaderer said.

The murders of Thomas Hunter and Sherman at the Hunter family's 3,700-square-foot home in Dundee were featured last year on "America's Most Wanted," and a $54,000 reward was offered for information.

Schmaderer tells Fox 42 that a special task force was created last year after investigators discovered Garcia had been in Omaha during all four of the murders, and the task force has been monitoring him for an unspecified amount of time.

When asked, Schmaderer said he and the task force believe Garcia "fit the elements of a serial killer," Fox 42 reports.

The police chief said Garcia is being held on four counts of first-degree murder and four counts of using a weapon to commit a felony.

Public records show that since 2003, Garcia has held medical licenses in California, Illinois and Indiana, but his temporary Indiana license expired in January.

A task force of local, state and FBI investigators has been working on the case, and its members believe Garcia fits all the criteria of a serial killer, Schmaderer said.

"We didn't feel this individual would stop unless an arrest was made," he said.

Schmaderer said investigators believe Garcia acted alone, and that they are also searching several places where Garcia has lived since 2001.

The Omaha attacks happened in neighborhoods where homicides are rare. The city averages about 40 per year.

One of the Brumbacks' three children, Darryl, said the family had no comment about the arrest. A male relative of Sherman's also declined to speak. The Hunter family didn't respond to a phone message seeking comment.

Authorities have released few details about the attack on the Brumbacks, other than manner in which they were killed. Their bodies were discovered in their west Omaha home on May 14.

The task force was set up after the Brumbacks' deaths to investigate whether they were tied to the unsolved 2008 killings. Schmaderer declined to say what led investigators to Garcia.

Click for more from Fox 42.

The Associated Press contributed to this report