Chadema secretary-general Dr Vincent Mashinji on Monday reported to the Dar es Salaam Central Police Station, following summons by the police on Friday to shed light on allegations that the party knows the people who attacked Singida East MP Tundu Lissu on September 7.
The police have also summoned Mr Lissu's driver.
Mr Lissu was shot outside his home in Area D in Dodoma by unknown attackers and is receiving treatment at Nairobi Hospital.
On September 9, Dodoma regional police commander Gilles Muroto ordered Dr Mshinji and Mr Lissu's driver to report to any police station to record statements on what they know about the attack.
But Chadema national chairman Freeman Mbowe said Mr Lissu's driver was in Nairobi receiving treatment for trauma.
"He is undergoing traumatic therapy. We decided to take him with us because he was traumatised after the event," Mr Mbowe said.