Fox News Channel had higher prime-time ratings than any other cable network last week for the first time since the aftermath of Hurricane Katrina in 2005.
The Nielsen ratings company said on Tuesday that Fox eclipsed the second-place USA Network by a quarter-million viewers on average. CNN also was buoyed by the big story and finished in third place.
The ABC, CBS and NBC evening news broadcasts collectively had 3.6 million more viewers than they had the week before.
Two bombs near the marathon finish line killed three people and injured more than 260 others. Two brothers were identified as the prime suspects. One died after a shootout with police, and the other was captured.