But over and over again, their efforts came up empty handed.
NewsWest 9 spoke with investigators to see where the case stands now.
"I met with Billie Dunn at the police department, she came here to report that she couldn't find her daughter," Kelsey Alexander, an Investigator with the Colorado City Police Department, said.
From day one, Alexander has been the lead investigator on the missing teen's case. After working on the case, Alexander along with City Police, realized they needed more manpower. That's when they called in the District Attorney's Office, Sheriff's Deputies, the Texas Rangers and even the FBI to assist.
During the investigation, officials found some disturbing things inside Hailey's home. They found print outs on serial killers, pornography and bestiality.
"It is not illegal to read about serial killers and what is considered historical cases. It is not illegal to possess pornography with willing participants. Bestiality is not illegal as long as it's not done in public. It's not illegal to possess, there is no legal action to follow up," Alexander said.
Haley's mothers boyfriend, Shawn Adkins, remains the only person of interest to this day. During a search warrant for Adkins back in March, Hailey's mother, Billie Dunn, lied about Shawn being inside her home. She was arrested and sentenced for lying to a police officer. Dunn has since moved to Austin and police have no way of getting in contact with her.
"She hasn't come in to talk with us, she hasn't called. I haven't heard from her in a very long while. Clint has remained active, he doesn't come in and talk much but we see and hear more from him and his family," Alexander said.
Even though there have been some developments. Police say they can't discuss those until they find Hailey.
"There is a lot of people that do want answers, what are you doing, what is going on. This is still an open investigation, this is still an active investigation. By me sharing information, I am not going to jeopardize this case or the investigation in any way just so people can feel good," Alexander said.
The search groups in Colorado City and Mitchell County have dwindled down but they haven't lost hope that Hailey will be found.
"Hailey will be found, she will. I know that and everyday, we are closer. Everyday, we are closer to her being found," Alexander said.
Police say the tips from people keep coming in. They continue to follow through with those very carefully. They keep re-reading all the evidence and revisiting every possibility as well as taking new information.