Police in Bangladesh say they're investigating the possibility that a local radical Islamic group was behind two attacks on publishing houses in the capital this weekend that left a publisher of secular books dead and three other people wounded.

Munirul Islam, a senior police detective, told reporters Sunday that the banned group Ansarullah Bangla Team was the main focus of an investigation into the attacks.

Publisher Faisal Arefin Deepan was found dead in his Dhaka office after the second of Saturday's attacks. The first attack left publisher Ahmed Rahim Tutul in critical condition, while two writers suffered less serious wounds.

The violence followed the killings of four atheist bloggers this year.

Deepan and Tutul had published works of Bangladeshi-American blogger and writer Avijit Roy, who was killed in February.