In the Philadelphia area, prosecutors have won convictions in a handful of such cases, some involving children. Robert Rivera of Upper Chichester refused to say what happened to his infant daughter after she disappeared in 1999. But he was convicted of second-degree murder in 2002. Katelyn Rivera-Helton has never been found.
Infants are a common category of bodiless murder victim, partly because their smaller bodies are easy to hide, DiBiase said.
"It's a horrific thing to say, but a bag weighing 10 pounds isn't going to call attention to the trash man," he said.
Rushdi told Upper Darby detectives he accidentally killed 7-month-old Hamza Ali after shaking him, and then disposed of the body at an undisclosed location, according to court documents.
"You will never find that baby," he allegedly told police.
Several searches near Rushdi's home in York and in Upper Darby, where the baby was last seen alive, have been fruitless.
The Delaware County District Attorney's Office charged Rushdi with first-, second-, and third-degree murder anyway, alleging the death was no accident.
The case is built on several pieces of circumstantial evidence, including Rushdi's stated dislike of the child, according to court documents.
Days before Hamza disappeared, Rushdi grabbed him roughly and hurt his shoulder, police said. He also told his girlfriend, Zainab Gaal, he wanted to get rid of Hamza and could "get away with murder," according to court documents.
Only an autopsy can determine how Hamza died. But the lack of the baby's body could work in the prosecution's favor, said Michael Chitwood, Upper Darby police superintendent.
"His defense is going to be 'shaken baby' - I already see that coming," Chitwood said. "But the fact that he won't tell us where indicates something far more heinous."
Mike Malloy, Rushdi's defense attorney, did not return a call from The Inquirer seeking comment. Rushdi is held in the Delaware County jail without bail.
The case against Rivera, the Upper Chichester man whose 20-month-old daughter has never been found, shares some features with Rushdi's case.
In 1999, Rivera told the girl's mother, "Katelyn is going to heaven, and I'm going to hell," and he initially told authorities he turned the girl over to strangers.
A former cellmate of Rivera's claimed Rivera said he suffocated Katelyn and buried her.
In 2002, a Delaware County jury acquitted Rivera of first-degree murder, sparing him the death penalty, but convicted him of a second-degree charge. He is serving a life sentence.
DiBiase said cases involving children are easier to prosecute because the defendants cannot convincingly claim the victims ran away. Traditionally, police have a harder time proving a missing adult was killed, although advances in technology have increased the rate of those cases since the 1990s.
"DNA is the main reason," DiBiase said. "But it's also the ability to track people through their ATM cards and social-media accounts and proving that they haven't logged into Facebook for six months."
In 2011, Bucks County authorities filed murder charges against Kenneth Patterson, accusing him of kidnapping and killing Diane Corado, an ex-girlfriend, even though her body had not been recovered.
The District Attorney's Office built its case on an eyewitness account of the abduction, blood later found on Patterson and in her abandoned car, as well as previous threats that Patterson made against her.
The case was set to go to trial this year. But Patterson struck a deal to avoid the death penalty, telling police where he hid Corado's body after beating her with a pipe.
Authorities have made similar deals over the years.
"Having been a prosecutor, I understand why prosecutors do that, particularly if they want to give some closure to the family," DiBiase said. "But it completely plays in to the hands of what these defendants are: control freaks."
Contact Ben Finley at 610-313-8118, firstname.lastname@example.org, or follow on Twitter @Ben_Finley. Get more Bucks County news at Inquirer.com/bucksinq.