Denver , Colorado ( CNN ) -- Using DNA to catch criminals has become common , but police in Denver , Colorado , this year demonstrated how the practice can be taken to a new level : They tracked down a suspect not through his DNA , but through that of his brother . Here 's how it happened , the Denver district attorney 's office said : . In February 2008 , two cars were broken into . Police found blood at both scenes and ran the samples through DNA databases but could n't find a match . Then , as part of a study being conducted by the district attorney 's office , investigators used new software to see whether the DNA in the blood was close enough to potentially be from a family member of someone in the criminal DNA database . The software came up with six potential matches . Five did n't pan out , but one led police to a convicted car thief and , ultimately , that man 's brother , Luis Jaimes-Tinajero . Jaimes-Tinajero pleaded guilty in September to one count of criminal trespass and received a sentence of two years ' probation . Attempts to contact Jaimes-Tinajero for this report were unsuccessful . District Attorney Mitch Morrissey called it one of the first cases in the country to use software to find familial DNA matches . `` Our hope here is to show that it works , which we have done , '' he said . `` I think it 's a valuable way to generate leads . '' Morrissey 's office developed the software tool with the Denver police , he said . He hopes to use it to solve murders , rapes and cold cases . The matches to family members wo n't be used as evidence itself , he said , but rather as a way to generate leads for investigators to explore , similar to the way police may use a witness report of a partial license plate . `` There 's no reason to bring this into court , '' Morrissey said . `` You use the science , you use the DNA , then you use a conventional investigation . '' But some privacy advocates are crying foul . `` Family members have done nothing wrong to get in the database , '' said Maryland defense attorney Stephen Mercer . `` And this is an example of the web of suspicion of people who have committed offenses being widened to include their entire family . '' Mercer has been fighting familial DNA searches since 2003 . He was part of an effort that led to Maryland being the first state to outlaw familial DNA searches . `` People have a reasonable expectation of privacy of their DNA , '' he said . `` It 's a basic violation of the Fourth Amendment of the Constitution '' Morrissey disagrees . `` I 've yet to hear anyone explain how this is a violation of the U.S. Constitution , '' he said . `` The bad guy abandoned the DNA at the crime scene . They have no expectation of privacy . '' Mercer also argued that even though the technique may be successful in certain cases , that does n't mean it is worth potential infringements on constitutional rights . `` If they want to drive down the street and do no-knock searches of homes , they would catch bad guys , '' he said . `` But at what cost to our society ? '' Morrissey hopes to have his office 's familial DNA study completed sometime in the coming year . In Colorado , the criminal DNA database includes people convicted of felonies . In the fall of 2010 Colorado will begin taking DNA samples at the time a person is charged with a felony . If a person is found not guilty or if charges are dropped , he or she can request to have the samples removed from the database . Mercer said that 's a slippery slope . `` Where it leads is toward the development of a universal database from the time they are born , '' he said . `` They want everyone in the database . ''
The FBI this year tracked down a car theft suspect using his brother 's DNA . Investigators compared the DNA from the scene to records in a criminal database . DA says the evidence is n't for the courtroom , but for building leads in an investigation . A defense attorney says it violates a person 's ` ` reasonable expectation of privacy ''