Missing woman's ex charged with trying to kill girlfriend

STUART, Fla. - The ex-husband of a Tennessee woman who disappeared nearly three years ago has been charged with trying to kill his girlfriend in Florida, reports CBS affiliate WTVF.

The attempted murder charge filed against Tyler Mook, 34, on Saturday stems from an October incident in which witnesses said Mook tried to drown his girlfriend following a fight aboard a boat in Florida, according to the station. The witness who relayed the incident to police was Mook's brother, according to a probable cause affidavit obtained by 48 Hours' Crimesider.

Mook was initially charged with domestic battery in the incident but the charges were upgraded over the weekend, the Martin County, Fla. Sheriff's Office says.

Mook is also named a person of interest in the 2011 disappearance of his ex-wife Shelley, with whom he had a young daughter.

Shelley Mook, a school teacher in Shelbyville, Tenn., disappeared after dropping their daughter off at Tyler Mook's home. Her car was later found burned in Murfreesboro, Tenn., near where the couple once lived. Her body has not been found.

Tyler Mook has not been charged in his ex-wife's disappearance, but Josh Devine with the Tennessee Bureau of Investigation told 48 Hours' Crimesider on Wednesday that Mook is still "very much a person of interest" and has not cooperated with their investigation into that case.

According to the probable cause affidavit, Tyler Mook's girlfriend flagged down a police officer Oct. 4 in Sandsprit Park in Stuart, Fla. and said Mook had tried to drown her. The woman "was visibly upset and was shaking," according to the affidavit.

Police say Tyler Mook began arguing with his girlfriend after his girlfriend told him to slow down while he was driving the boat fast through a "No wake manatee zone." Mook allegedly attempted to rip his girlfriend's bathing suit top off and threw her overboard into the water.

Police say Mook followed the woman into the water and attempted to hold her under. She was able to fight her way back to the surface, but police allege Mook "immediately pushed her under again."

Mook's brother intervened to help the girlfriend, according to the affidavit.

She told police that Mook said, "No one disrespects me in front of my family. I will killer her."

Police say the woman was "adamant" that Mook would have drowned her had his brother not helped.

Mook was later found at his aunt's residence in Palm City, where he was arrested.