West Yorkshire Police close investigations without identifying a suspect in three quarters of household burglaries and two thirds of reported vehicle thefts, new analysis shows.
They also ended around four in 10 shoplifting cases with the same outcome
Across the three offences, around 22,000 investigations in West Yorkshire were shut with no suspected culprit in the frame, the Press Association found.
The revelations prompted warnings that victims could be put off reporting offences, while criminals are given a "green light to reoffend".
Police chiefs say increased demand and reduced officer numbers mean they have to prioritise cases where there is a realistic chance of prosecution.
The figures were extracted from Home Office crime outcomes data, and cover the 12 months to March 2018.
They show that out of the 14,957 household burglary cases opened over that period by West Yorkshire Police, 76% were categorised as "investigation complete - no suspect identified".
This is used when a reported crime has been investigated "as far as reasonably possible" and the case is closed pending further investigative opportunities.
Of the total burglary cases, West Yorkshire Police brought 587 people to court.
Labour MP Yvette Cooper, who chairs the Commons Home Affairs committee, said: "Too many investigations are closing without suspects being identified and we are hearing increasing reports of the police being too overstretched to investigate.
"Police forces are under immense pressure with rising serious and violent crime and changing patterns of crime alongside cuts in the numbers of officers and PCSOs.
"These figures suggest that investigations into volume crimes are now being hit. Failing to identify suspects gives criminals a green light to reoffend."
The country's larger police forces tended to have higher percentages of cases closed without a suspect being identified.
Alex Mayes, of charity Victim Support, said: "News like this could undermine confidence in the criminal justice system and prevent people reporting in the future."
Of the 4,769 vehicle thefts recorded in West Yorkshire, 66% ended up with no suspect being identified, while in the 18,556 shoplifting cases, 7,758 of them were closed with the same outcome.
The police charged 146 suspects with car theft, and 3,859 for shoplifting.
RAC Insurance spokesman Simon Williams said motorists will be "shocked" by the findings.
"This is a sign that thieves have found ways around car security systems and have ways of selling vehicles on with little or no fear of being caught," he said.
Deputy Chief Constable Amanda Blakeman, National Police Chiefs' Council lead for acquisitive crime, said increased demand and fewer officer numbers have led to forces prioritising cases with a realistic prospect of prosecution.
She added: "Police investigate all cases of theft, burglary and shoplifting. Particularly for these types of offences, police focus on targeting prolific offenders, organised crime networks, and ensuring prevention measures by homeowners and businesses are in place."
A Home Office spokesman said: "We expect the police to take all reports of crime seriously, to investigate and to bring the offenders to court so that they can receive appropriate punishment.
"However we recognise that crime is changing and police demand is becoming increasingly complex. That is why we have provided a strong and comprehensive £13 billion funding settlement to ensure the police have the resources they need to carry out their vital work."