Families of murder and manslaughter victims need more sensitive treatment by police, courts and support groups, a survey suggests.
Many families are bewildered by the aftermath of the death
Victim Support questioned 41 of the 1,000 bereaved relatives it had helped over the last year.
Some felt they were being offered the wrong kind of help by groups like Victim Support itself.
The study suggested many victims show signs of post-traumatic stress, and need help with basic day-to-day tasks.
Domestic matters like paying household bills can easily be overlooked during the chaos and grieving that follows a bereavement, the charity said.
One of the authors of the report, Peter Dunn, said relatives of murder victims often found they were unable to touch their loved ones after death - and in some cases were physically restrained - because the bodies were "evidence".
Often families were unable to hold funerals for several months because of difficulties in getting the body released from the coroner.
And in some cases, in court, the prosecution barrister would ignore the family, making them feel "completely sidelined".
Too often they met with "officiousness and bureaucracy", he said.
In another instance, one woman, whose child had been killed, was told by her GP she could not receive counselling as it was "not cost efficient".
"People shouldn't have to be in a situation where things get even worse before they get help," he said.
The study found that relatives had often had to cope with turmoil when a killing had occurred in the family home and it had been sealed off as a crime scene.
Many would have appreciated somebody who would take charge of the clearing up when they returned, as well as screening telephone calls, the survey suggested.
Frances Lawrence, the widow of murdered headteacher Philip Lawrence, told the BBC that after such a death "as well as the grieving, you have a great sense of powerlessness".
"It seems that the state takes over. You can be very powerless," she said. "You need to know that that system is working in the interests of the victim."
Mrs Lawrence spoke of her trauma at learning through a national newspaper - not the authorities - that her husband's killer had been let out on day release over the weekend.
She called for a debate between the "parties involved" about how much victims' families should be told.
"I feel that we should never water down the gravity of an offence just because of the passing of time," she said.
The Victim Support survey also found that victims whose cases became part of the criminal justice system found difficulty in coping, because following through the process could slow down reactions to the tragedy, and intensify feelings of powerlessness and anger.
One mother said she wanted ongoing contact with the police.
She told support workers: "Even if they have nothing to tell me, I have questions."
Victim Support says it will use the results of the study to change how its volunteers are trained to improve family liaison services.
Rose Dixon, from the charity Support After Murder and Manslaughter, said: "On the whole the police are actually doing a lot of training for their police family liaison officers.
"But it's the general court system where I think that families feel they're unsupported."
The Home Office says that relatives unhappy with the way they are treated will be able to complain directly to a Parliamentary ombudsman as of April.
It also plans to introduce victims' advocates in courts for murder and manslaughter cases "to make sure that their voice is heard in court".
The whole process will be overseen by a Victims Commissioner.
A spokeswoman welcomed the report.
"We will want to work closely with Victim Support to see how support services can be improved," she said.
Conservative home affairs spokesman Edward Garnier called for improvements in managing the release of prisoners.
"At the very least, families should be told that the man or woman who damaged their own lives, their own family, is about to be released on this condition or that and into this place or that," he said.