Tahir Zarif - who prosecutors claim shot Mr Javeed in the legs, throat and mouth - is at the centre of an international manhunt after flying to Pakistan following the killing last February.
A six-week trial was shown distressing CCTV footage of Mr Javeed being gunned down at point-blank range as he tried to escape from his catering supplies firm in Digbeth, Birmingham.
Speaking after three other men were convicted of conspiracy to commit robbery, detectives said Zarif, 25, was thought to have passed through Heathrow Airport with his mother five days after the murder.
The trial at Birmingham Crown Court was told Mr Javeed was killed after being asked to take a masked gunman to a safe.
Zarif's business partner Suraj Mistry was acquitted of murdering Mr Javeed but convicted of manslaughter, conspiracy to commit robbery and possession of firearms with intent to cause fear of violence.
Jurors cleared a second defendant, Lemar Wali, of murder, manslaughter and firearms charges but convicted him of conspiracy to rob.
The court was told Mistry, 26, of Laundon Way, Leicester, took part in the raid along with Zarif, of Osmaston Park Road, Derby, after both men were driven to the scene by Wali.
Wali, 19, also of Osmaston Park Road, told the trial he took Mistry and Zarif to the warehouse in Rea Street South but did not know they were armed.
The raid was launched after sacked delivery driver Sander Van Aalten, 50, provided inside knowledge to the gang, including a plan of the warehouse drawn on the back of a water bill.
Van Aalten, of Kyrwicks Lane, Birmingham, admitted conspiracy to rob before the start of the trial.
Commenting after the trial on the ongoing operation to locate Zarif, Detective Chief Inspector Martin Slevin, of West Midlands Police, said: "This was a planned, callous, cold-blooded murder - there is no other way of describing it.
"The offenders planned this offence over a number of weeks and days - they brought firearms to the offence location, one fitted with a silencer.
"They brought cable ties with which to incapacitate all of the staff, and this was only made possible by the information provided by an inside man."
The officer added: "We would urge anybody who has information where Tahir Zarif is currently living or being harboured to contact West Midlands Police, or Crimestoppers in confidence.
"If you're overseas, contact your embassy and pass that information on, so that we can attempt to bring him back to the UK to face trial for this offence."
Mr Javeed's daughter, Lilas Javeed, from Ilford in London, backed Mr Slevin's plea for information about Zarif.
The 30-year-old counsellor said: "There is no real closure when it's murder.
"There has been three people brought to justice. It's three less criminals roaming the streets but of course it's very important for us that the other person is brought back.
"I have faith that the relevant authorities will work together to bring him back and face trial so that we can get justice."
Mistry, Wali and Van Aalten are due to be sentenced on September 27.