The mother of Turky al-Dandani, the most wanted suspect, was quoted as saying in Okaz newspaper: “I appeal to Turkey to give himself up like Gamdi did”.
The mother was referring to Ali Abd al-Rahman al-Gamdi, who had turned himself in on Thursday, according to Saudi authorities.
“If you want to see me happy and satisfied, please hurry up and turn yourself in. They will reach you sooner or later,” said the 70-year-old mother, Eida Raji Saleh al-Balhoud.
Al-Dandani, 27, is on the top of a list, of 19 wanted men, published by the Saudi authorities just a few days before the 12 May bombings.
Authorities launched a large-scale manhunt after the bombings in Riyadh that killed at least 34 people, including nine bombers.
Al-Dandani had traveled to Afghanistan two years ago and came back five months later, his brother Saud told the newspaper.
The mothers of Abd al-Aziz al-Mugren and Othman al-Omari also urged their sons to surrender.
The two are on the list of 19 and had also been to Afghanistan.
They are believed to belong to al-Qaeda network and are suspected of involvement in the Riyadh bombings.
Saudi Interior Minister, Prince Nayef bin Abd al-Aziz, told Okaz that the suspected Islamists would end up in the hands of the security forces.
He therefore said, that it was “better for the suspects to surrender”.
About 50 suspects, including eight women, have been arrested following the Riyadh bombings, Prince Nayef said.
The highest religious authority in the kingdom called on Saudis not to shelter the remaining fugitive suspected Islamists, al-Hayat newspaper reported.
“We must never protect those who are behind an incident in the country, but denounce them,” Grand Mufti, Sheikh Abd al-Aziz al-Al-Sheikh told the London-based daily.