A 41-year-old man has been arrested on suspicion of attempted murder after a firebomb attack on a house.
A woman in her 60s had been critically ill but is now stable following the fire in Leigh on 16 October.
Greater Manchester Police said the man was also arrested in connection with a fire at a house in Huyton, Merseyside.
A force spokesman said a 22-year-old man arrested on Thursday in connection with both fires was bailed pending further inquiries.
Earlier this week Andrew Bamford, 37, of no fixed address, was charged with attempted murder over the fire in Montreal Street, Leigh.
Officers have linked this fire to the blaze two days earlier at a house on Mardale Road, Huyton.