The sentence will be pronounced by the special Maharashtra Control of Organised Crime Act (MCOCA) court on August 27.
Jamsandekar was shot dead in March 2008 at his Asalpha residence in suburban Ghatkopar. Gawli was arrested on May 21, 2008 and has been in custody since then.
The charge sheet said that a sum of Rs 30 lakh was paid to the Gawli gang for the job. The trial had commenced from October 2010.
One of the accused, Bala Surve, died during trial, while three accused were acquitted for lack of evidence.
Special MCOCA judge Prithivaraj Chavan said in the open court that it had been proved that Gawli was a member of organised crime syndicate and was engaged in extortion.
The court said that Gawli, along with other accused, had hatched a conspiracy (to kill Jamsandekar).
Following the conviction, when the judge asked the accused about their say on the quantum of the sentence, all of them said that they should be shown some leniency.
Special public prosecutor Raja Thakare said that he wanted to argue on the point that the accused be given capital punishment. The court said that it would hear the arguments on Monday.
Later, Gawli moved an application saying that he must me kept in a special cell with proper security, as there is a threat to his life. After hearing the application, the court directed the jail authorities to take appropriate steps.
Describing Gawli's conviction as a blow to the underworld, Joint Police Commissioner (Crime) Himanshu Roy said, "For the first time, a gang's kingpin was convicted in any case. We will seek death penalty for the don."
"This will also deter the criminals associated with organised crime from committing heinous crimes."
As many as 49 cases, including the murder case, were registered against Gawli in the city, police said, adding that some of the trials were still pending.
