There were two pleas submitted to Metropolitan Magistrate Noor-un-Nabi on Monday.
One sought approval for tests on samples of their blood, hair, stool, skin and clothes besides various organs.
The other was for profiling their DNA.
To confirm the killers’ identities, the police want to collect samples necessary from their family members.
Twenty-two persons died after gunmen, armed with rifles, pistols and explosives stormed Dhaka’s Holey Artisan Bakery and O’ Kitchen on Jul 1. Two police officials died when they tried to break the siege.
They murdered 20 hostages inside the upscale cafe, mostly foreigners, before being shot dead by commandos the next morning.
They were later identified as Meer Saameh Mubasheer, 19, Rohan Ibn Imtiaz, 20, Nibras Islam, 20, Khairul Islam Payel, 22 and Shafiqul Islam Ujjal, 26.
Police claimed the cafe’s pizza chef Saiful Islam Chowkider was the sixth attacker who is named in the case filed over the deadly terror attack.