HOUSTON, Texas (KTRK) -- A teen accused of leaving a woman to die during an alleged carjacking was caught trespassing days before the murder and was offered help by a stranger, who said the suspect refused the assistance.Dave Lazar, a home builder, said he caught 17-year-old Teihjon Shannon squatting in his model home, where he was sleeping in a bed and casing neighbor's homes."Oh, I've been dealing with this guy for about three weeks," Lazar said. "When I heard that this young man was part of a heinous murder, it really bothers me. It bothers me because we had him and he was let out."During his first encounter, he said he had a frank conversation with the teen and tried to help."I sat him down, felt sorry for him. He gave me a story where he was homeless living in the woods," Lazar recalled.Lazar said the teen walked out on him, refusing food and some cash. So, Lazar warned him to never return.But it was days later when Lazar caught the teen sleeping in an upstairs closet, spending an entire day hidden as the builder worked downstairs."Basically (I) body-blocked him as he was trying come down the stairs. Called 911. They came and arrested him," Lazar said.Shannon was charged with criminal trespassing and granted a personal bond of $500. The teen, though, jumped bail the next day, missing his court hearing.Then, detectives said he and another man, David Jones, took the life of 75-year-old Clara Barna during a carjacking."And the neighbors found her decomposing body and I had that guy in my sights?" Lazar said, expressing difficulty recalling his interaction with the teen. "I have a hard time dealing with that to be honest with you."The district attorney's office told Eyewitness News the criminal trespass charge was Shannon's first offense as an adult. And because it was a misdemeanor, he was granted a standard $500 bond."If I would have just made sure he was in jail a little bit longer, maybe he would not have done the events he did in the following days and weeks," Lazar lamented.In a matter of weeks, Shannon wound up with two mugshots, with charges escalating from a misdemeanor to capital murder."If the system does justice, he'll be behind bars for capital murder and, who knows, maybe at that point, I go (to jail) as a visitor and tell him, 'Remember when I told you it wouldn't end well for you?'" Lazar said.