The man arrested in connection with the 2000 slaying of Linda Watson and the 2003 killings of her mother and a neighbor is a veteran of the Tucson Fire Department.

The department said Monday that David Watson โ€” Linda Watsonโ€™s 46-year-old ex-husband โ€” has been placed on unpaid leave after his arrest Saturday night on suspicion of three counts of first-degree murder in the deaths of Linda Watson; her mother, Marilyn Cox; and a neighbor, Renee Farnsworth.

David Watson has been employed as a firefighter since 1995. He was promoted to captain in 2007, the department said.

โ€œThe Tucson Fire Department is saddened to learn about the circumstances related to one of our employees. Our thoughts and prayers go out to the friends and family of the victims,โ€ fire Capt. Barrett Baker said in a news release.

David Watson was arrested without incident at his home and was booked into the Pima County jail.

He was the prime suspect all along, but it took investigators DNA technology, multiple tips over the years and 15 years of investigation to finally make the case, said Chief Deputy Chris Nanos of the Pima County Sheriffโ€™s Department.

There are a number of details about the investigation that the Sheriffโ€™s Department cannot reveal until Watson gets his day in court, Nanos said.

โ€œThese are very hard cases. Theyโ€™re not easy to solve,โ€ he said. โ€œBecause I believe you did something is one thing, but to be able to prove it in court beyond a reasonable doubt โ€” that takes a lot more.โ€

Nanos described David Watson as an โ€œevil man.โ€

Linda Watson was a 35-year-old mother involved in a custody battle with her ex-husband over their 4-year-old daughter. The Sheriffโ€™s Department said the dispute may have been David Watsonโ€™s motive in the three slayings.

Court records showed a lengthy battle, which began in February 1998 when Linda Watson filed for divorce. Linda and David Watson fought over child custody, visitation, child support and division of property.

The battle continued even after Linda Watson disappeared from her northwest-side home on Aug. 21, 2000.

Sheriffโ€™s detectives discovered the door to Watsonโ€™s home, in the 2600 block of West Curtis Road, open. They found a shattered coffee cup and traces of her blood, detectives said.

Three years later, Cox, 63, and her friend and neighbor, Farnsworth, 53, were gunned down in the driveway of the same home. Cox had moved into the home after her daughter disappeared.

Cox had fought for the right to visit with her granddaughter and was returning home after dropping the child off following her first unsupervised visitation when she and Farns-worth were shot to death on May 7, 2003, Nanos said.

Before her death, Cox told authorities about two visits David Watson made to her house, once in camouflage clothing and both after dark.

Cox also feared for her life, fortifying her house, never leaving at night without a friend and buying a gun, according to Star archives. She also emailed her attorney during this time saying she was worried she might disappear like her daughter.

David Watson denied any roles in the deaths, telling the Star shortly after Cox and Farnsworth were killed: โ€œAll I can say is I wasnโ€™t involved. I didnโ€™t have anything to do with it.โ€

After Coxโ€™s death, the child at the center of the custody dispute was raised by David Watson and a stepmother. The two have since divorced. The daughter is now 19 years old.

Officials declared Linda Watson dead in 2006, but her body wasnโ€™t found until 2011 when remains discovered in a desert area were identified as hers through DNA.

In 2007, the Sheriffโ€™s Departmentโ€™s cold-case unit definitely linked the three homicides and said information in the case was โ€œsnowballing.โ€ They said then that the suspect โ€œhad made some mistakesโ€ they were capitalizing on. But no arrest was made.

The department โ€œpushed forwardโ€ with new information and investigative leads from witnesses and Linda Watsonโ€™s skeletal remains, Nanos said.

โ€œWeโ€™ve always believed that David Watson was responsible for the brutal murder of his ex-wife, for the savage slayings of Ms. Cox and Ms. Farnsworth,โ€ he said. โ€œToday, we believe we have enough to prove that.โ€


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Contact reporter Yoohyun Jung at 520-573-4224 or yjung@tucson.com. On Twitter: @yoohyun_jung