Russia withheld a crucial piece of information from the U.S. before the Boston bombings, U.S. officials say, bolstering a concern that distrust between the two governments erased an opportunity to avert the disaster.

In 2011, Russia sent an alert to the Federal Bureau of Investigation about alleged bomber Tamerlan Tsarnaev, prompted in part by text messages between his mother and a Russian relative. The texts suggested Mr. Tsarnaev was interested in joining militant groups that Russia blames for attacks in the Caucasus region, according to U.S. officials briefed on the investigations.

U.S. officials call these text messages the most important in a series of missed signals between the two countries. One U.S. official characterized at least one of the text messages as generally discussing jihad, but without any specific mention of terrorism plans.

The U.S. officials say they learned about them roughly a week after the April 15 bombings. Several officials say such precise information would have led to a deeper examination of Mr. Tsarnaev, who died a few days after the bombing in a police confrontation. His brother and alleged accomplice remains in custody.

The information Russia withheld "would have allowed the bureau to open an investigation where you could track [Mr. Tsarnaev's] communications," said House Intelligence Committee chairman Mike Rogers (R., Mich.). "To me, that's where the ball really got dropped."