Thousands of suspects have been released under investigation by police, a power detectives can use as an alternative to bail.
Unlike bail, suspects released under investigation (RUI) are not always subject to strict time limits and conditions. Hundreds have remained under investigation for months.
Police chiefs say its use allows them more time to build a case but critics believe it is used too widely and can leave suspects in limbo for months and potentially put victims at risk of coming into contact with their attackers.
The legal system was reformed by the Government in 2017 in an attempt to stop people being subject to police bail for long periods. A 28-day time limit was imposed for bail in most cases but it also gave forces the option to release under investigation. Further changes could be possible after it was announced last week the use of RUI was to be reviewed.
Figures showed Staffordshire Police released 11,061, including 45 people initially arrested on suspicion of murder and another 33 suspected of attempted murder. It was also used 280 times for rape suspects and dozens more times for suspected paedophiles.
Some 462 people remained under investigation for at least a year and 93 for two years. The longest someone was under investigation was 927 days, for alleged grievous bodily harm.
West Midlands Police released 28,989 suspects under investigation since 2017. These did not include suspected murderers but did feature people arrested on suspicion of sexual offences, robbery and possession of weapons.
The National Police Chiefs' Council say investigations are now more complex due to increased use of CCTV and mobile phones, meaning detectives need more time to crack cases.
But the Law Society has called for RUI time limits and regular updates for those subject to it.
“Our evidence showed how RUI is being used for a wide range of crimes including indictable offences such as rape and murder,” said Law Society president Simon Davis.
“There are concerns that alleged victims and witnesses to crimes are at risk as suspects are not made subject to bail conditions.
“Under RUI, innocent suspects can be left in limbo for months or even years and victims can face an open-ended wait for justice."
A Staffordshire Police spokeswoman said: "An underlying and key consideration in the use of RUI to manage suspects must always be the necessity to support and protect victims and witnesses - especially those who are identified as vulnerable - and ensure public safety. Management and scrutiny around the use of RUI is a focus for the force, including ensuring it is used appropriately.
“We frequently make applications for suspects to be remanded and, if we believe there are risks, we take steps to ensure alleged victims and the wider public are safeguarded."
Liberal Democrat Parliamentary candidate for Wolverhampton North East, Richard Maxwell, said: “These figures show the government’s soundbite claim that they are ‘on the side of victims’ is a cynical spin. Every extra day a case is left in this limbo is another day when victims have their lives placed on hold.
"Suspects are left with uncertainty; victims of crime also live in fear of being confronted by the accused.”