Egypt's interior ministry said Thursday it had identified the bomber who targeted a Palm Sunday service at a Coptic Christian church in the northern city of Tanta, killing 28 people.
The previous day, the ministry had named the man it said was the bomber who struck outside a church in the Mediterranean port of Alexandria.
A total of 45 people were killed in the two attacks, which were claimed by the Islamic State group.
On Thursday, the ministry issued another statement saying that the Tanta bomber had now been identified as well.
"DNA tests carried out on the family of a fugitive member and the remains of the suicide bomber... made it possible to identify him as Mamduh Amin Mohammed Baghdadi, born in 1977 in Qena province, where he lived," it said.
It said he was a member of a "terrorist" cell, and announced the arrest of three other members of the cell.
The ministry also said it would increase the reward for information leading to the arrest of any member of the cell linked to Sunday's attacks from 100,000 Egyptian pounds (about $5,500) to 500,000 pounds.
On Wednesday, the ministry said it had identified the perpetrator of the Alexandria attack as Mahmud Hassan Mubarak Abdullah, born in Qena in 1986.