Many of them have traveled from the southwest China city of Chongqing, where Bo had been party boss until his ouster last month, to the home of Li Zhuang, a Beijing lawyer who they say they hope can help get justice for jailed relatives, The Washington Post reported.
"My place has become the petitioning office for Chongqing people," Li said. "They know I am against what Bo Xilai did in Chongqing."
Bo faces charges of corruption and abuse of power while his wife, Gu Kailai, is accused of killing British businessman Neil Heywood.
More than 4,000 people were jailed during an anti-crime campaign Bo began in late 2007 in what he called a crackdown on gang activity and lawlessness. Critics say the campaign was part of an effort to punish rivals and pressure local businesses to give money.
Those jailed in the campaign included not only gang members but also police officers, local government officials and wealthy businessmen, and about 1,000 people were sentenced to forced labor while dozens were executed after quick trials that didn't follow judicial procedures, the Post said. Many of those arrested said they were tortured in custody.
The newspaper said China's Communist authorities have not indicated a willingness to revisit the anti-crime campaign and the cases of thousands who remain imprisoned.