• by Wayne Friedman , April 22, 2013

Wall-to-wall Monday to Friday coverage of the Boston Marathon bombing sent broadcast and cable networks ratings soaring -- with NBC topping all networks on Friday, when suspect Dzhokhar Tsarnaev was caught during the prime-time period.

For the entire week, the big three cable news networks more than double their total day audience, up to Nielsen live plus same day 1.3 million total average viewers for the week April 15-9. This was 120% higher than the previous Monday to Friday period, April 8 to 12.

Fox News Channel, the longtime leader in cable network news, continued to take the top spot averaging 1.9 million up 80% from the previous week. It was averaging 1.08 million from April 8 to 12.

CNN made the biggest gains — up 300% to 1.4 million viewers, averaging 363,000 the previous week. The big Boston story made the least impact for MSNBC — up 70% to 633,000 from 374,000.

On Friday, as the dramatic search for Tsarnaev reached its conclusion, ratings spiked even higher -- especially for the broadcasters. During the 8 p.m. to 11pm (ET) period, NBC earned 8.933 million viewers;  ABC, 7.207 million; CBS, 6.741 million; Fox News Channel, 5.970; CNN, 5.371 million; and MSNBC, 1.717 million.

NBC peak viewership at 8 p.m. (ET) pulled 10.70 million viewers; ABC was at 7.8 million; Fox News, 7.6 million; CBS, 6.9 million; CNN, 6.8 million; and MSNBC, 1.7 million