"We have DNA evidence ... from the crime scene. The DNA of the criminals is there," police chief Dhahi Khalfan said on the Arab satellite television channel Al Arabiya.
Khalfan said police had "categorical DNA proof on one of the assassins" and fingerprint evidence from several other suspects, providing "100 percent" proof of their identities.
The murder of Mabhouh, whose body was found in a Dubai hotel room on Jan. 20, mounted international pressure on Israel after Dubai said that Israeli agents, most using stolen Western identities, carried out the hit.
But Israel argued there was no evidence that its Mossad spy agency was behind the hit on Mabhouh, one of the founders of Hamas' military wing.
Dubai police published details of 26 suspects together with passport photographs.
The international police organization, Interpol, circulated warrants for the arrest of 11 suspects after Dubai released their names and passport details.
Dubai later said it had 15 other suspects, and Khalfan added that warrants for their arrest would be circulated through Interpol next week.
The revelation of stolen identities being used by suspected Israeli agents caused a diplomatic outcry, with the Australian, British and Irish governments launching their own investigations into the identity theft.