Chowdhury, owner of Dulhan Jwellers at Chittagong’s New Market, was kidnapped from his residence at the Old Telegraph Road in Chittagong on Feb 11.
He filed a case against a senior official of the elite force several months ago in connection with a separate incident.
His family hinted that he might have been abducted by RAB for filing the case.
Police headquarters formed the probe committee headed by Chittagong Metropolitan Police (CMP) Additional Commissioner Banaj Kumar Majumder on Mar 2.
Other members of the committee are Additional Superintendent of Police of Chittagong Md Iltutmish and RAB-7 Deputy Commander Md Nazmul Hassan.
The committee submitted its report to the Police Headquarters on Tuesday.
According to the report, RAB or any other law enforcers had nothing to do with his abduction.
Chowdhury, who was found unconscious at Kongso Bazar of Burhichong Upazila in Comilla on Feb 17, said he could not recognise any of his captors.
CMP official Majumder said they had visited the RAB-7 headquarters and checked CCTV cameras and registers there.
They also checked the register of the detective police. But no information was found, he said.
The probe committee had heard the statements of eight people including the abducted gold trader and Major Raqibul Amin of RAB-2, an accused in the case filed by Chowdhury.
The CMP official said Chowdhury had given the same statement before the probe committee as he had given in the court.
Maj Raqibul told the probe committee that he was at his workplace in Dhaka when Chowdhury was abducted in Chittagong.
Chowdhury alleged that RAB had seized 80 bharis of gold, which he was sending to Dhaka through his driver Babul Paul at the end of last year.
He filed a case against Raqibul as he did not get back the gold.
The RAB official was once posted in Chittagong.
The case was under investigation, said Majumder, adding that the investigating officer concerned would look into the matter.
The Criminal Investigation Department (CID) is now probing the case.