Dubai investigators have collected crime scene DNA samples and fingerprints of some of the suspects in the high-profile slaying of a Hamas operative, a senior official said Friday.

In an interview with Al-Jazeera television, Dubai police chief Lt. Gen. Dahi Khalfan Tamim said the evidence was collected at the luxury hotel in the Gulf city state where Mahmoud al-Mabhouh was found dead in his room Jan. 20.

Dubai authorities have accused Israel's Mossad spy agency of being behind the slaying, and have identified at least 26 suspects of the alleged hit squad that traveled to Dubai on fake identities and forged European and Australian passports to kill al-Mabhouh.

At least 15 of the suspected killers share names with Israeli citizens, further fueling suspicions the Mossad was behind the hit.

Tamim told Al-Jazeera the suspects that entered al-Mabhouh's room to kill him left the room tidy and locked the door from inside — and latched the chain lock — when they left to make it look like he died in his sleep.

"They made the room look as if there had been no struggle," he said. "Everything was in order, as if the man was asleep. They left and closed the door perfectly and put the chain lock on as if the man had shut it himself."

Tamim said the fingerprints and DNA samples will allow Dubai authorities to positively identify the suspects if they are ever arrested, even if they have changed their appearance.

"Fingerprints don't lie. The picture may lie, the camera may lie, and the face may change. But the DNA remains in everyone's body," he said. "There are samples from a number of them (suspects) which they left behind. We have these samples, and when they are arrested ... the fingerprints and DNA samples will be used."

Dubai authorities have two Palestinians suspects in custody, and Tamim said security camera video show that one of the Palestinians was directly involved with the foreign suspects and had meetings with them.

Israel has neither confirmed nor denied involvement in al-Mabhouh's killing.