Watch a report from ITV Anglia's Raveena Ghattaura
Police have identified 52 possible sites where a newborn baby might have been placed into a bin, before being transported to a recycling centre in Needham Market.
Thursday marks exactly four weeks since the girl was discovered among waste material by a member of staff at Sackers' yard on Ipswich Road.
It is believed the baby, which was dead when it was found, was placed in a commercial bin on either the 13 or 14 May, the day it was transported to the recycling centre.
Officers investigating the death are focussing on two deliveries made to the yard, and have put up posters appealing for more information at the 52 locations visited by the lorries.
Possible route and pick-up locations 1:
Possible route and pick-up locations 2:
Suffolk Police have renewed their appeal for any information which would lead to an identification of the baby girl.
Chief Superintendent Tonya Antonis said: "While we continue to review hundreds of hours of CCTV footage, we are appealing to anyone who may have seen anything unusual or have any information, however limited, to come forward.
"During the past four weeks, we have carried out many enquiries and have been working closely with partner agencies to gain further information that may help us identify the baby girl but this has so far proved unsuccessful.
"It may be difficult to come forward with information, particularly if you have concerns about a family member or friend, but if you know who this baby girl is and how she came to be placed into a bin, I urge you to come forward and help us as soon as possible please.”
Specialist officers spent three weeks searching the waste yard, and have seized several items for analysis.
Chief Superintendent Antonis added: "I can’t imagine the impact [the investigation's] had on the staff that found her.
"I have to say the staff at Sackers have been absolutely tremendous and the support has gone in for the staff and for the drivers of the lorries as well."
Enquiries have also been carried out at over 830 commercial and residential properties to try and find out where the baby came from.
A post-mortem investigation on the baby's body took place on Tuesday, 19 May, but it was unable to make any definitive findings.
Following the discovery, which was made at around 3pm on 14 May, police also expressed concern for the health of the mother, as the baby was likely to be 48 hours old at most.
However, appeals to identify and find her have been unsuccessful so far.
Chief Superintendent Antonis said the case has had a "profound effect" on her officers:
To get in touch with Suffolk police: