Demarco is 41 years old, born January 28th, 1976. According to one of his Facebook profiles (he has three: 1, 2, and 3), he attended Harrison High School in Evansville, IN. Little is known about his work history but what we do know is that he has a long line of criminal history.
Demarco has 53 cases in his name according to Doxpop.com and 50 of those are criminal cases dating back to 1993 when he was just 17 years old. Cases range from small infractions like public intoxication to felonies like criminal confinement, battery, burglary, etc. There are too many cases to list so I will list a few that are relevant.
Relevant Criminal Records:
11/18/2003: Battery by means of a deadly weapon (case 82C01-0311-FC-01225)01/30/2007: Domestic battery, possession of marijuana, possession of paraphernalia (case 82D02-0701-MC-00088)
08/2/2007: Dealing in hash oil, hashish, or marijuana and neglect of a dependent (case 82C01-0708-MC-00746)
02/10/2010: Dealing in hash oil, hashish, or marijuana (case 82C01-1002-FD-00206)
03/25/2013: Criminal confinement, strangulation, battery resulting in bodily injury to a pregnant woman, and intimidation (case 82D02-1303-MC-00448)
11/21/2014: Unlawful possession of a firearm by a serious violent felon, possession of methamphetamine, possession of paraphernalia, possessing a look-a-like substance, and 2 counts of habitual offender (case 82C01-1411-F4-004756)
03/21/2016: Domestic battery committed in presence of child under 16 (case 82C01-1603-F6-001633)
06/17/2016: No contact order with Cara Beckerle, Aleah Beckerle or the minor child who is not his daughter (case 82C01-1606-MC-001333)
06/21/2016: Unlawful possession of a firearm by a serious violent felon, habitual offender and 3 counts of criminal recklessness committed with a deadly weapon (case 82C01-1606-F4-003580)
I consider these cases relevant because they show a consistent pattern of behavior. It's quite clear from his history that he is a drug dealer and he has violent tendencies. All cases listed with the exception of the March 2013 case list Cara Beckerle's address as his home address. Now whether that's true is another story since records often don't get updated but I thought it was worth mentioning. Also, the final case listed is the one in which Demarco fired shots in the Beckerle home just a few weeks prior to when Aleah disappeared.
Some people have speculated that Demarco killed Aleah, possibly when he fired shots in the house and others question whether someone killed Aleah as revenge to Demarco.
