A major newspaper says U.S. agents were warned years before the 2008 Mumbai terrorist attack that an American man was training in Pakistan with the group that carried it out, and helped plan the attack.

says the FBI received the tip about David Coleman Headley from his wife in August of 2005. Citing sources close to the case, it says she told FBI agents that her husband had undergone intensive training with the militant group Lashkar-e-Taiba and was in contact with extremists.

Report: FBI Warned Ahead of Mumbai Attacks

The report, co-authored with the journalism foundation ProPublica, says Headley went to Mumbai five times to scout locations for the terrorist assault on the Indian city.

Report: FBI Warned Ahead of Mumbai Attacks

The attack lasted three days, left 166 people dead and more than 300 others wounded.

Report: FBI Warned Ahead of Mumbai Attacks

The newspaper says the FBI interviewed Headley's wife three times, but that he remained free to travel around the world on the scouting missions. He was not arrested until almost a year after the Mumbai attack, and is now in U.S. custody.

says U.S. anti-terrorism agencies did warn Indian counterparts in 2008 about a possible plot to target Mumbai, but it is not clear if those warnings were based on the tip from Headley's wife.