Taufiq Qureshi alias Abdullah, one of the eight people acquitted by the trial court in the 2002 Ghatkopar blast case, was arrested from Noida on Tuesday.
Taufiq is also an accused in the blast case in a Sai temple in Hyderabad in 2002.
A Special Investigation Team (SIT) from Tamil Nadu and the Uttar Pradesh Anti-Terrorism Squad (ATS) arrested him from the Morna bus stand.
He is wanted in Tamil Nadu in various cases and has been absconding from 2008.
"The SIT received a tip-off that Taufiq was somewhere near Delhi. They contacted us and through electronic surveillance and our information network, we arrested him on Tuesday.
"He was planning to move to Saudi Arabia and had planned to obtain a passport under a fake name," said RN Mishra, deputy superintendent of police UP ATS (Western UP) wing, that has its headquarters in Noida.
Taufiq's acquittal in the Ghatkopar blast is currently being challenged in the Bombay high court.
"In 1999, Taufiq was involved in an attempt to murder case and in 2000, a murder case was registered against him in Tamil Nadu. Till then he used to operate as a hired killer.
"He then fled to Saudi Arabia and there he met a terrorist group and became a fundamentalist," Mishra said.
"In 2002, he was arrested in Tamil Nadu and detonators were recovered from him. Gelatin sticks were recovered from his accomplices," Mishra added.