"The accusations against Morsi look like payback by the former regime, which appears to be vigorously returning to Egypt's political scene," Brotherhood spokesman Jihad al-Haddad said Friday.
Morsi was announced detained on Friday for 15 days pending investigation into accusations that he had "conspired" with the Gaza-based Hamas movement to carry out "hostile acts" inside Egypt.
He is also charged with involvement in attacks on police facilities and personnel, according to Egyptian state news agency MENA.
The ousted president faces additional charges of helping prisoners – including himself – escape from jail, sabotaging public property, and abducting security officers and soldiers.
According to MENA, Morsi has been confronted with "evidence" confirming the charges against him.
Morsi, Egypt's first democratically elected president, was overthrown by the army on July 3 after mass protests against his regime.
The army subsequently suspended the constitution and installed Adly Mansour, the head of the Egypt's constitutional court, as interim president under a transitional roadmap for the country's political future.
Morsi, a leading Muslim Brotherhood figure, has not been seen in public since his overthrow by the military.
Meanwhile, thousands of Morsi supporters continue to stage daily demonstrations and sit-ins to defend his democratic legitimacy and demand his reinstatement.