Former Vice President Luis Giampietri, one of the hostages of the Tupac Amaru siege of the Japanese Ambassador's residence in 1997, accused Soberon of being an advocate for the terrorists.
The Tupac Amaru rebels captured the Japanese ambassador's residence in Lima in December 1996, holding 72 hostages for over four months before Peruvian forces stormed the compound, rescuing all but one of the hostages and killing all 14 rebels inside.