* Kabiru Sokoto was initially suspected mastermind
* Boko Haram Islamists see Christians as enemies
ABUJA, Dec 20 (Reuters) - A Nigerian court sentenced a member of Islamist group Boko Haram to life imprisonment on Friday for his involvement in bombings including a 2011 Christmas Day attack on a Catholic church near the capital that killed 37 people.
The militant group Boko Haram claimed responsibility for the bombing of St. Theresa Catholic Church in Madalla, on the outskirts of Abuja, which also wounded 57 in the deadliest of a series of attacks at Christmas.
Kabiru Sokoto was initially suspected of being the mastermind of the Christmas bomb, although the Federal High Court's Justice Adeniyi Adetokunbo-Ademola found the prosecution had only proved that he knew it was going to happen and failed to disclose this to the authorities.
Ademola found him guilty however of being the mastermind of a bungled coordinated strike in the northwestern city of Sokoto in July the same year. Several bombs were planted by government buildings there, including next to the police headquarters, but were discovered before they were detonated.
He also noted that Sokoto was a member of an "illegal terrorist organisation Boko Haram". President Goodluck Jonathan declared the Islamist rebels -- seen as the main security threat to Africa's top oil producing nation -- a terrorist group in June.
Boko Haram, like many hardline Islamist groups, sees Christians as infidels who must either convert or be crushed. A wave of attacks on churches two years ago seemed aimed at triggering a sectarian war in a country with the world's largest mixed Muslim and Christian population.
Sokoto slipped the net the day after his arrest but was recaptured the following month.
He received a life sentence for masterminding the failed Sokoto bombs and 10 years for not informing authorities of the Christmas attack.
Jonathan launched an all-out offensive against Boko Haram seven months ago in its stronghold in the northeast.
Initially this appeared to temper the violence as soldiers secured towns, cities and semi-desert bases.
But Boko Haram fighters have survived many assaults during the 4-1/2-year-old insurgency. After retreating this year to remoter areas, they have mounted deadly counter-attacks -- including one on several military barracks and the air force base in the main northeastern city of Maiduguri this month. (Reporting by Camillus Eboh; Writing by Tim Cocks; Editing by Rosalind Russell)