Essex Police have arrested a 26-year-old man on suspicion of the attempted murder of a woman in Southend and a 39-year-old woman on suspicion of conspiracy to murder.
Both remain in custody for questioning, the force said.
Officers investigating the case have already made five other arrests in connection with their inquiries.
Previously, three men and a woman were arrested on suspicion of grievous bodily harm with intent and a 16-year-old boy from Southend was arrested on suspicion of attempted murder.
All five have been danced until mid-July.
The probe was launched after a 19-year-old woman was found with multiple potentially life-changing injuries at St Marys Court, off Victoria Avenue, shortly before 4am on Monday.
Essex Police’s serious crime directorate is continuing to appeal for the public’s support with the investigation.
Information which could help the police’s investigation can be reported online at mipp.police.uk.
Anonymous reports can be made by contacting the independent charity Crimestoppers online at crimestoppers-uk.org or by calling 0800 555 111.
