HARTFORD, Conn. — The challenges law enforcement officials face in investigating a suspected murder without a body are on display in the case of missing Connecticut mother of five Jennifer Dulos.

Police documents reveal what some experts believe is overwhelming evidence compiled by investigators against her estranged husband, Fotis Dulos. Authorities have filed charges against him and his girlfriend, but only tampering with evidence and hindering prosecution counts.

"Where's the murder charge?" Norman Pattis, Fotis Dulos' lawyer, said recently, asking a question on the minds of many observers as he downplayed the evidence.

Law enforcement experts say prosecuting a murder case without a body was nearly impossible decades ago. It remains difficult but has become easier in recent years because of evidence not available in the past including cellphone location information, surveillance cameras and new DNA testing, they say.

Jennifer Dulos, 50, of the wealthy suburb of New Canaan, disappeared May 24 after dropping her and Fotis Dulos' five children off at school. She hasn't been seen since. Police say they found traces of her blood at her home, on items in trash bags investigators believe were discarded by Fotis Dulos and on the seat of a pickup truck authorities believe he drove on the day she vanished.

Fotis Dulos and his girlfriend, Michelle Troconis, have pleaded not guilty to the tampering and hindering charges, and both are free on bail.

When there's no body, authorities lack the best piece of evidence, said Tad DiBiase, a former federal prosecutor and author of the 2014 book, "No-Body Homicide Cases: A Practical Guide to Investigating, Prosecuting and Winning Cases When the Victim is Missing."

"The body can tell you how the murder happened," he said. "The body can tell you when the murder happened. The body could tell you where the murder happened. When you don't have those things, it makes it a real challenge to try to solve those types of cases."

When there is no body, investigators are faced with having to find compelling circumstantial evidence and usually take more time building their case before bringing a murder charge, because you only have one shot at trying to prove murder, DiBiase said.

Connecticut State Police officials declined to comment Tuesday on whether the lack of a body has stalled the investigation.

Fotis Dulos, 52, has denied any involvement in Jennifer Dulos' disappearance. In an interview that aired on NBC's "Dateline" on Monday night, he repeated his past comments that he believes she is still alive. Jennifer Dulos vanished in the middle of contentious divorce and child custody and visitation court proceedings.

"Right now, my life is a mess," he said. "I wish she were here to sort this mess out and I'm still hoping that she's going to show up."

An arrest warrant released last week revealed the array of evidence police have compiled in the case. Police say they have surveillance video showing Fotis Dulos in Hartford disposing of bags of items containing Jennifer Dulos' blood; traffic and school bus camera video of him driving a pickup truck to New Canaan on the morning she disappeared; surveillance video of him getting the truck washed and detailed days after she vanished; and evidence that Jennifer Dulos' DNA was found on the truck seat.

Up until a few decades ago, prosecutors were extremely reluctant to file murder charges without a body, due to a longstanding English common law doctrine dating back to the 17th century, DiBiase said. In Chipping Campden, England, three members of the Perry family were hanged for the killing of William Harrison, who disappeared in 1660. Several years later, Harrison turned up alive claiming he was kidnapped and sold into slavery.

But forensic science advances have made that doctrine obsolete.

In an infamous Connecticut case without a body in 1986, prosecutors were able to win a murder conviction against Newtown resident Richard Crafts , who put his wife's body into a woodchipper. Authorities were able to identify Helle Crafts from tiny fragments of bone, teeth and hair, and had circumstantial evidence against Richard Crafts.

State prosecutor Stephen Carney, who is not involved with the Dulos case, won a murder conviction in 2010 in the case of 15-year-old April Dawn Pennington, of Montville, whose body was never found after she was raped and killed in 1996. Last week, the state Supreme Court overturned a lower court ruling that ordered a new trial for the convicted killer, George Leniart.

"The fact that no body was ever located presented challenges, but that did not mean that there was not significant evidence of a death including the fact that a 15-year-old girl had vanished in the night never to have been seen by anybody despite a nationwide search," Carney said.