Question: Which English convicted drug-dealer killed two persons in a gun and grenade ambush?

<P0-S0> On 18 September 2012, Police Constables Nicola Hughes and Fiona Bone, two Greater Manchester Police officers, were killed by Dale Cregan in a gun and grenade ambush while responding to a report of a burglary in Greater Manchester, England. <SEP> <P1-S0> SS "Emidio" was a 6912-ton tanker of the General Petroleum Corporation (later Mobil Oil), which became the first casualty of the Imperial Japanese Navy's submarine force action on California's Pacific Coast. <P1-S1>  It was one of four attacks on shipping, the others being "Samoa, Larry Doheny," and "Montebello", all attacked off the coast of California before Christmas. <P1-S2>  "Emidio" was sailing in ballast from Seattle, Washington en route to San Pedro, California. <P1-S3>  The Japanese submarine I-17 found "Emidio" off Cape Mendocino on the early afternoon of 20 December 1941, immediately attacking with its 14-cm deck gun. <P1-S4>  Realizing that the situation was futile, Captain Farrow raised a white flag and gave the order to abandon ship. <P1-S5>  Ignoring the surrender, the I-17 continued firing from its deck gun, blasting three crew members who were lowering a lifeboat overboard. <P1-S6>  Four crew members remained on board: a radio operator and three engineers. <P1-S7>  When the I-17 fired a torpedo, it struck the engine room and killed two of the engineers and injured the third. <P1-S8>  In total the I-17 hit the tanker with five shells from its 14-cm deck gun and one torpedo killing five crew members. <P1-S9>  A Catalina flying boat of 44 Patrol Squadron attacked I-17 with depth charges, but the submarine dove and escaped. <P1-S10>  The Coast Guard Cutter "Shawnee" rescued the remaining 31 survivors who had rowed 16 hours to Humboldt Bay. <P1-S11>  The abandoned tanker drifted north and broke up on the rocks off Crescent City. <P1-S12>  The bow drifted into the harbor, where it lay until scrapped in 1959. <P1-S13>  The remains of the hull are still in the harbor, near a commemorative plaque. <P1-S14>  The site has been declared a California Historical Landmark #497. <SEP> <P2-S0> The attack occurred on a Friday morning. <P2-S1>  ETA had observed similar convoys from the factory and planned their ambush based on information that they had gathered. <P2-S2>  The convoy consisted of four vehicles, the first carrying technicians, the third mortar devices produced by the factory and the second and fourth vehicles carrying three civil guards each. <P2-S3>  The vehicle left the factory at 0730 and at approximately 0815, had to slow down at a part of the road which consisted of numerous bends. <P2-S4>  The ETA members had chosen a spot near a small hill, where they were hidden from view by dense vegetation. <P2-S5>  After allowing the vehicle carrying the factory workers to pass, ETA launched a grenade at the second vehicle, causing it to be stuck in a layby and then attacked the civil guard's vehicles with assault rifles, machine guns and grenades, firing over 100 shots. <P2-S6>  In order to ensure that no civil guards survived, the ETA members approached the vehicles and threw a hand grenade into the first civil guard's vehicle. <P2-S7>  When they repeated this with the second vehicle, two ETA members, Gregorio Olabarría Gorrotxategui Bengoa and Javier Argote, were killed as a result of injuries suffered when they failed to escape in time before the grenades exploded. <P2-S8>  One of these was subsequently found 6 kilometres away from the attack, having apparently been moved there by his comrades. <P2-S9>  At 0845, a man had approached a bar near the scene and had asked in Basque for medical assistance. <SEP> <P3-S0> Dale Christopher Cregan (born 6 June 1983) is an English convicted drug-dealer and murderer who was sentenced to a whole life order in prison for four counts of murder (including the killing of two police officers) and three separate counts of attempted murder, meaning that he will never be released from prison.