Tulsiram Pawar, a childhood friend of retired Naval officer Kulbhushan Jadhav, said on Tuesday that he would spare no effort in keeping the demand for his friend’s release from a Pakistani prison alive. He has started a signature campaign against the death sentence awarded to Mr. Jadhav.Mr. Pawar, who grew up with Mr. Jadhav in Lower Parel, said he was still trying to come to terms with the news. “I am starting a signature campaign demanding Mr. Jadhav’s release and will be getting in touch with our mutual friends who used to stay here. I am already in touch with a few, and we are planning peaceful protest marches as well,” he said.He is exploring the option of turning to the social media. “I do not have much knowledge about social media or the Internet, and am seeking the help of the younger generation.” Mr. Jadhav, son of a retired Assistant Commissioner of Police, stayed in the building behind N.M. Joshi Marg police station, which now houses Unit III of the Mumbai Police Crime Branch. The building earlier had quarters for police officers. Mr. Pawar, who stays in the opposite building, said he had been friends with Mr. Jadhav for as long as he could remember, and that his earliest memories with him are of roaming in the narrow lanes behind Bawla Masjid and playing together for hours. Sources said Mr. Jadhav’s family left the city late on Monday night, and are believed to be in Pune.