Police in Arizona may be one step closer to solving a 15-year-old cold case murder of a Tucson mother and the subsequent related slayings of her mother and neighbor . David Duane Watson , a 46-year-old Tucson firefighter , was arrested without incident Saturday on charges he killed his ex-wife Linda Watson , 35 , in what detectives say motivated by a custody dispute over their daughter . Police say the dispute continued after Watson 's murder as her mother Marilyn Cox , 63 , tried to obtain visitation rights . Three years after her daughter went missing , Cox and her neighbor Renee Farnsworth , 53 , were shot dead in the driveway of Linda Watson 's home . Tragic : Police say Linda Watson , left , was killed by her ex-husband David Watson during a 2000 custody dispute over their daughter Jordynn , right . Three years later , they say Mr. Watson murdered Linda 's mother Marilyn Cox , center , as she tried to gain visitation rights over the girl in 2003 . Cold case closed ? Seen here upon his arrest late Saturday , David Watson has been charged in the murder of his ex-wife , ex mother-in-law and an innocent neighbor . Police said at a press conference on Saturday that Mr. Watson had been the prime suspect in the murders from the start , reports the Arizona Daily Star . Watson has been charged in all three homicides , with police cited DNA evidence . Chief Deputy Chris Nanos said sheriffs never gave up on the cases , writes Tucson News Now . 'It just goes to show you that the men and women of this department are bulldogs , ' said Nanos . 'We 'll keep tracking you , we 'll find you and you will get punished for the crimes you do . ' Linda Watson was reported missing in August 2000 after she failed to pick up her daughter from the home of David Watson . She was last seen by a friend who 'd dropped her off following a church function . Inside the home were found Ms. Watson 's pager , Bible and purse . The door to her home was found open and her blood was discovered at the scene . Linda Watson was reported missing in August 2000 after she failed to pick up her daughter from the home of David Watson . She was last seen by a friend who dropped her off at her Tucson home after church . Her body would not be found until 2012 . Police say David Watson had been the primary suspect since 2000 , but have only now tied him to the crime with what a Sheriff 's Department official said Saturday was 'DNA evidence ' After her disappearance , Marilyn Cox , became intent on finding her daughter and devoted her life to the search . She -- along with the girl 's paternal grandfather -- was granted visitation rights for her granddaughter . However , Cox said at the time that Watson obstructed those rights , so she petitioned for a review . In May 2003 , with another custody battle heating up , Cox was shot dead in a drive-by shooting in the driveway of the home from which her daughter had disappeared years before . Her neighbor , Renee Farnsworth , was also killed in the shooting . Meanwhile . Linda would not officially be declared dead until 2006 . Her body would n't be found until six years after that when remains discovered in the Arizona desert turned out to be hers . Watson was scheduled to be arraigned Sunday morning at Pima County jail where the Sheriff 's Department would recommend a $ million bond , reports KGUN . Marilyn Cox ( right ) was fighting to exercise her visitation rights over Jordynn Watson when she and her neighbor Renee Farnsworth were gunned down in a 2003 drive-by shooting outside the very home from which Linda had disappeared three years earlier .
Pima County Sheriffs say that Watson , 46 , killed his ex Linda Watson while they took over custody of their daughter in 2002 . Three years later , police say Watson murdered his ex wife - in - law in a drive - by shooting at the very home where Linda had first vanished . Marilyn Cox had been fighting for visitation rights over her granddaughter - she was shot down alongside her neighbor Renee Farnsworth in 2003 .