Eric Muhia, Paul Mbugua, and Georgia Wainaina were freed from custody at 9 p.m. on September 13. Police had earlier linked them to the September 9 shooting before completing their investigations.
Mbobu, a former chairperson of the Political Parties Disputes Tribunal, was killed along Magadi Road as he drove toward his Karen home. According to police, two men on a motorcycle trailed his vehicle before one approached on foot and fired several bullets through the driver's window.
Nothing was stolen during the attack, which detectives described as a premeditated assassination.
The 55-year-old lawyer had built a successful practice in commercial litigations but was also dealing with many debt cases at the time of his murder. He at some point represented Captain (Rtd) Kung'u Muigai, a cousin to former President Uhuru Kenyatta, in his controversial 33-year-old 443-acre coffee farm case.
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The Senior Counsel Bar (SCB) questioned the possible link between the killing and the case, with detectives reportedly probing the speculation.
"The SCB further notes that on the same day that Mbobu was murdered, a post appeared on social media, in which one Captain (Rtd) Kung'u is captured complaining about a 33-year-old case of his, in which the late Mbobu was at some point his advocate," Senior Counsel Philip Murgor stated.
"Is it a coincidence that he is then gunned down on the same day? Whatever the case, no stone should be left unturned by the DCI, to ensure that the perpetrators of this heinous crime are brought to book."
Days after the shooting, detectives picked up Muhia, Mbugua, and Wainaina as persons of interest. They were held while police carried out forensic phone analysis, ran ballistic tests on a recovered firearm, and investigated their alibis.
Lead defence lawyer Musa Maulid accused the police of mishandling the case.
"The arrest and detention of Eric Muhia, Paul Mbugua and Georgia Wainaina was malicious, unjustified and a reckless abuse of police powers," said Maulid.
"It is regrettable that the police dragged the names of honest, law-abiding citizens through the mud before conducting proper investigations," he added.
Maulid stressed that the forensic and ballistic results, together with independently verified alibis, had cleared the three of any involvement.
"These findings confirm what has been true from the very beginning: they had no involvement in this crime," he observed.