(ABC NEWS) -- An Indiana doctor has been arrested on suspicion of four murders in Nebraska that occurred in 2008 and 2013.
All four people were connected to Creighton University's medical school, from which the suspect was fired more than a decade ago.
Dr. Anthony Garcia, 40, was arrested by Illinois State Police on Monday when he was driving near the Indiana border, according to police. Garcia has been living in Terre Haute, Ind.
Garcia was pulled over in a traffic stop and arrested without incident, police said. He showed signs of alcohol intoxication and had a .45 caliber handgun with him, Omaha Police Chief Todd Schmaderer said at a news conference on Monday.
"The task force has been monitoring Dr. Garcia's movement for a period of time," Schmaderer said.
"In 2008, the murders of Shirlee Sherman and Thomas Hunter caused great concern for the Omaha community," Schmaderer said. "In May 2013, the murders of Dr. [Roger Brumback] and Mary Brumback further placed the Omaha community and especially the Creighton pathology department on considerable edge."
Authorities believe Garcia is responsible for a 2008 Omaha home invasion where Sherman and 11-year-old Thomas were stabbed to death. Thomas was the son of Creighton pathology department professor Dr. William Hunter and Sherman was the family housekeeper, according to police.
In May, Creighton pathology professor Dr. Roger Brumback was shot to death and his wife Mary Brumback was fatally stabbed, police said.
Garcia was a resident in the Creighton pathology department from July 2000 to June 2001.
"[Garcia's] employment ended when he was terminated by Dr. Hunter and Dr. Brumback," Schmaderer said. "We do know why he was terminated. The specifics I won't say here today. But it was for a form of erratic behavior."
The chief said the announcement of the arrest can provide a "sense of closure" to the families, university and community that were shaken by both sets of murders.
Members of the Hunter and Brumback family did not respond to requests for comment and authorities do not know if Garcia has retained an attorney.
Creighton University would not comment further on the circumstances surrounding Garcia's termination but released a statement from the university's president, the Rev. Tim Lannon.
"We continue to keep those affected by these events in our thoughts and prayers," Lannon said. "And we continue to pray for all of the special task force members still executing search warrants throughout the country."
Public records show that Garcia has held medical licenses in California, Illinois and Indiana since 2003, according to ABC's Indianapolis affiliate WRTV.
Schmaderer said task forces across the country are still searching several places where Garcia lived and worked.
"It is imperative that I do not divulge too much of the evidence that law enforcement has on this case because it is ongoing," he said. "At this point in our investigation, we are led to believe that he committed the murders alone and we are investigating the history of Dr. Garcia."