Two arrests are made after an attack that left a 93-year-old woman in a critical condition in hospital.
Emma Winnall suffered a fractured skull, a broken arm and wrist and a partially severed finger at her home overnight on 30 April.
A woman, 56, and 28-year-old man from the Hall Green area of the city are in police custody after being arrested at about 06:30 BST on Thursday.
A £5,000 reward has been offered for information about the attack.
A spokesman for West Midlands Police said: "The dawn arrests were made following routine police enquiries and were not a result of information from the public."