Egyptian authorities arrested a top member of an Islamist terror group suspected of involvement in pipeline bombings that have disrupted gas supplies to Israel and Jordan, Egyptian state media reported on Sunday. The Palestinian news agency Ma'an reported that the detainee, Mohammed al-Teehi, was also being investigated for an August terror attack in southern Israel that killed eight people.Teehi, of the armed Islamist group Al-Takfir Wa Al-Hijra (Excommunication and Exodus), was arrested in the northern coastal city of El-Arish, Egypt's news agency MENA reported. Yedioth Ahronoth newspaper reported in September that an Israeli army investigation had revealed the attack, near the southern city of Eilat, had been planned by Egyptians operating in Sinai.The Sinai gas pipeline was attacked on Thursday for the seventh time this year. Egyptian authorities have struggled to maintain full control over the peninsula, especially since state security was disrupted by the overthrow of President Hosni Mubarak in February.Authorities see Teehi as the mastermind behind attacks on police stations in the city and he has topped a government "wanted" list, MENA said. Some residents of al-Arish confirmed that he belongs to a "well-known religious current" but said he cannot move because of a car accident that fractured his pelvis.Egyptian officials say limits on troop numbers in Sinai under a 1979 peace treaty with Israel make it harder to secure the area, which local Bedouin say has been neglected for decades. Some have taken to smuggling and gun-running to scrape a living. Egypt's 20-year gas deal with Israel, signed in the Mubarak era, is unpopular with the Egyptian public, and critics argue that the Jewish state was not paying enough for the gas.Previous explosions have closed the pipeline, run by Gasco, Egypt's gas transport company, a subsidiary of the national gas company EGAS, for weeks.The armed forces launched a security sweep in August to root out suspected Islamist gangs and, according to security sources at the time, captured four Islamist militants as they prepared to blow up the pipeline in El-Arish.