( CNN ) -- Blood discovered during the search for Pennsylvania trooper shooting suspect Eric Matthew Frein is not his , state police said Monday . Droplets of what appeared to be blood on the steps of a covered porch near the town of Cresco , Pennsylvania , turned out to be human , the Pennsylvania State Police said . But DNA testing showed the blood was n't Frein 's , police said . Material found on the inside of a screen porch door at a nearby home was n't blood at all , police said . Neither has any link to the search for Frein , according to police . Police read excerpts of notes they say suspect left . On Friday , a law enforcement source speaking on condition of anonymity told CNN that there was no reason to believe that Frein was injured or that the blood was Frein 's . Frein , 31 , is suspected in the September 12 ambush shooting that left Cpl . Bryon Dickson dead and Trooper Alex T. Douglass wounded outside the Pennsylvania State Police barracks in Blooming Grove in northeast Pennsylvania . Police have not spoken about a possible motive , other than that Frein has talked and written about hating law enforcement . Authorities have said that a review of a computer hard drive used by Frein shows that he had planned the attack . Police : Suspect planned ambush for months . He has eluded escape despite a massive police search around Canadensis , Pennsylvania , where his family has a home . Police say they think a woman taking a walk Friday night saw Frein , armed with a rifle and his face dabbed with mud , in a wooded area near the eastern Pennsylvania town of Swiftwater , about 8 miles southeast of the Canadensis area . CNN 's Jason Hanna , Shimon Prokupecz and Ray Sanchez contributed to this report .
Stains investigated for link to trooper shooting suspect Frein do n't pan out , police say . one stain was blood , but not Frein 's ; the other was n't even blood . Frein is suspected in September 12 ambush of 2 officers , 2 of whom died . He may have been seen September 12 night , police say .