Police have carried out checks near a stream in Smethwick where the body of a six-month-old baby was found hidden a week ago.
Officers investigating the death of Troy Simpson revisited the Stanhope Road area of Smethwick between 9pm on Monday night and 2am yesterday in an effort to gather further information from witnesses.
Troy was found dead in Thimblemill Brook last Wednesday, a day after being reported missing from his home in a nearby street.
A West Midlands Police spokesman said detectives were particularly keen to speak to anyone who may have seen a man or a woman carrying a blue JD Sport carrier bag in the area before the child was found.
Anyone who can assist detectives in their inquiry should contact the incident room at Smethwick police station on 0121 626 9148, or anonymously on the Crimestoppers number: 0800 555 111.
Troy's father and grandmother have appeared in court accused of perverting the course of justice. Theresa Ann Simpson, Sherwain McCoy Smith and a 17-year-old girl, who cannot be named for legal reasons, were all remanded in custody charged with plotting to conceal the boy's body.
Simpson (47) of The Uplands, Smethwick, Smith (20) of Arden Road, also Smethwick, and the teenage defendant were ordered to appear at Birmingham Crown Court on February 20.