Police in Tauranga are examining bloody clothes and objects related to a serious assault.
A police patrol found Russell Munday, 49, with serious head injuries early last Thursday. He is in a critical condition in Waikato Hospital.
Detective Senior Sergeant Greg Turner says ESR scientists have examined a building on Devonport Road where it is believed Mr Munday was attacked.
Mr Turner says they will examine bloody clothing and other items to try and identify his attackers.
Police want to hear from taxi drivers and members of the public who were on Devonport Road between 2.30am and 5am last Thursday, 29 December.