A Kentucky police officer has been fired for allegedly tampering with an investigation regarding the missing girlfriend of his brother, who has just been named the only suspect in her disappearance.

Crystal Rogers, 35, has been missing since July 3. Her boyfriend, Brooks Houck, has claimed the last time he saw the mother of five was the night before, playing games on her phone.

The only clue in Rogers disappearance was her maroon Chevy Impala, which was found unlocked and with a flat tire on Bluegrass Parkway on Saturday.

Inside were her keys, purse and uncharged phone.

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Brooks Houck has been named the only suspect in the disappearance of his girlfriend Crystal Rogers (pictured here together with their two-year-old son). Rogers has been missing since July 3

Houck claims Rogers, 35, was up late playing games on her phone on the night of July 3 and that when he woke up the next morning she was gone

The only clue in Roger's disappearance was her maroon Chevy Impala, which was found unlocked and with a flat tire on Bluegrass Parkway on Saturday with her uncharged phone, keys and purse

Rogers' family is relieved that police have finally named him a suspect, something they believed in their own gut 'from day one'.

Houck's brother Nick has been fired from the Bardstown Police Department and accused of tampering with the investigation

Nelson County Sheriff Ed Mattingly officially named Houck a suspect on October 16.

'Thank god something is happening,' Rogers' mother Sherry Ballard told LEX 18.

'I've been waiting for this for a long time, for three months now.'

It was also revealed that Brook Houck's brother Nick had been fired from the Bardstown Police Department following his suspension last month.

Nick has been accused of warning his brother that detectives were planning to question him and later told him not to talk to police.

Authorities said the former officer also failed a polygraph test.

Police released an interview that followed the test, where the polygraph examiner told Nick Houck the questions he had problems with were regarding Crystal Rogers.

'I don't give a god d*** what your f***ing computer said," Houck responds in the interview."I'm telling you that I have been 100 percent honest with you.'

Rogers' parents said that when they heard the interviews, the first thing that went through their minds was 'that they done it'.

'That he's just as guilty as Brooks,' they told WHAS 11. 'And that there's at least one more involved if not two.'

Filmed interviews between a detective and Brooks Houck were released (pictured), and show him claiming that Crystal went out that night with friends

Police also released footage of Nick Houck being interviewed after he failed a polygraph test. The examiner in the video tells Nick the questions he had problems with involved Rogers

Shortly after his girlfriend disappeared, Houck said he had not been concerned because the couple had a 'stressed relationship' at times

Interviews between a detective and Brooks Houck were also released, and show him claiming that Crystal went out that night with friends.

'They do these fantasy parties,' he tells the examiner. 'All these girls get together, its not uncommon for them to stay out...the better part of the night if not the whole night.'

The detective then brings up a text obtained from Rogers' phone, where she told a friend that she and Brooks had found a babysitter to watch their two-year-old son that night.

'It's our first time being kid-free for awhile. We're gonna enjoy ourselves,' the detective recites from the text in footage obtained by WDRB.

'I don't know,' Houck responds.

Shortly after his girlfriend disappeared, Houck said he had not been concerned because the couple had a 'stressed relationship' at times and Crystal would sometimes 'cope or deal' by spending the night at her cousin Sabrina's house.

Rogers pictured with her five children. Houck is the father of Rogers' 2-year-old son

Brooke Ballard, Rogers' sister, doesn't believe Houck's stories add up and said he hasn't offered to search at all or 'do anything for the family' since his girlfriend disappeared

Houck said he was '100 percent completely in this' and said his results to a polygraph test were inconclusive

'I was not in the least little bit alarmed in any way, shape or form,' he told Nancy Grace on HLN.

'She spent the night there on several occasions.'

Houck said the 'maximum' period of time Rogers would stay away 'has only been a day to a day and a half most', so he called her once in the morning before attending a July 4 gathering.

Brooke Ballard, Rogers' sister, did not believe Houck's stories added up.

'You just don't go to bed one night and now know she's gone and then not worry when she left the baby,' Ballard told ABC News.

Ballard said Houck didn't offer to search at all 'or do anything for the family' since Rogers disappeared.

Houck said all his effort in searching for his girlfriend has been done 'behind the scenes with the Nelson County Sheriff's Office' and said he has been '100 percent completely honest with everyone'.

'I've been 100 percent cooperative in every thing that has been asked of me,' he told Nancy Grace. 'I've not asked for any kind of legal advice or assistance, an attorney of any nature.'

'I'm 100 percent completely innocent in this.'

Houck took a polygraph test but the results were inconclusive, he said.

Officer Mattingly said at this point police are assuming Rogers is dead.