There are cases that are the stuff of detectives' dreams, full of flashy police work, fancy technology and forensic drama. Then there are the "whodunits."
And so it is with the fatal shooting of 67-year-old Surinder Singh, the Elk Grove grandfather who was gunned down during his daily afternoon stroll early this month.
His friend, 78-year-old Gurmej Atwal, also was struck in the gunfire and remains in critical condition.
Elk Grove police and law enforcement observers agree it's a case with significant hurdles, one that likely will hinge on a resident's helpful tip or an informant's loose lips.
"This case is going to be broken by someone giving us that one vital tip," said Officer Christopher Trim, a police spokesman.
Police never publicly disclose all evidence they have in a case, especially one as high-profile as Singh's killing. But even here, Elk Grove authorities have made it clear that leads are scarce.
They have a public, outdoor crime scene tough for collecting evidence yet no apparent witnesses; a vague description of a truck seen in the area; and skid marks that victims' relatives say are at the scene, though it's unclear if they are related to the crime.
Perhaps worst, they have two victims whose lives offer no road markers drugs, gangs, domestic turmoil to offer detectives direction.
"We have to go on what we have," Trim said, "and we have very little."
Police and community members have raised the specter that the men were targeted because they are Sikh, a religion whose members have been mistaken for Muslims since the Sept. 11, 2001, terrorist attacks.
Like many traditional Sikh men, both victims had thick beards and wore turbans.
Police have no evidence it was a hate crime, Trim said, "but there's no evidence to eliminate that possibility, either."
Absent a definite motive, though, detectives must rely on "good, old-fashioned police work," Trim said, which includes mining the community for information.
Elk Grove police also tried a new tactic, conducting a checkpoint near the crime scene at 4:30 p.m., when the shooting occurred, days after the shooting. Officers questioned drivers and came up with a few leads, Trim said.
The scene of the crime is busy and noisy and has produced no witnesses, Trim said, so officers have expanded their canvass. He also indicated that police have talked to residents along the victims' usual walking route. Trim declined to discuss other investigative methods.
"On one side, it's not like 'Barney Miller.' On the other side, it's not 'CSI,' " he said, referring to the popular TV shows. "It's a fine balance of being proactive and being reactive. But in a case like this, we are by far more proactive."
Law enforcement experts in the region were leery to discuss another department's case but agreed that Elk Grove detectives have their work cut out for them.
"I'll tell you, just from what I've read, they have a real difficult case on their hands," said retired Sacramento police Sgt. John Cabrera, a longtime homicide investigator. "Your only hope is someone comes forward."
Sgt. Drew Wyant, who supervises the Sacramento County Sheriff's Department homicide unit, said "whodunits" require a much larger canvass than usual.
"The more people you talk to, the better," he said. "You have to cast a wide net."
He also noted that surveillance cameras can be helpful in cases like these. In the murder of correctional officer Steve Lo, for example, a neighbor's footage proved a valuable source of evidence.
Through analysis, skid marks can tell what size car left them, Wyant said though detectives still must link them to the crime.
Wyant, too, knows the frustration of investigating a killing in which the victim's life offers little clues.
Almost four years after 39-year-old John Pogacar was found stabbed to death in his home, the case remains unsolved. Detectives recently revisited the case, but a motive remains elusive. Pogacar appeared a friendly, hardworking, honest man, Wyant said.
"Why was he targeted? We don't know," he said. "It doesn't make sense."
Elk Grove police and their local colleagues said the Singh case is still fairly fresh, and they're optimistic that someone eventually will come forward with a tidbit knowledge of a friend behaving strangely, say, or a memory of an older, beige Ford F-150 running a red light that will ignite the case.
And there is Atwal, the surviving victim, who has not yet been physically able to give police a statement.
"That could be their gold at the end of the rainbow," Cabrera said.
Or the key tip could come from an informant, observers said someone disturbed by an innocent man's killing or trying to save their own skin.
Such was the case in the June 2007 killing of Mary Ourk, a 21-year-old community college student shot as she was driving her friend home after a night of dancing.
The case went cold for more than a year before an informant caught up in an unrelated federal prostitution case suggested police take a look at the man later convicted in Ourk's death.
"That's what's going to happen somebody's going to drop a dime," said former Sacramento County Sheriff John McGinness, who is among those watching the Singh case. "People can't keep their traps shut on that stuff."
HOW TO HELP
Anyone with information about this case is asked to call Elk Grove police at (916) 714-5115 or Crime Alert at (916) 443-HELP. Callers can remain anonymous. The reward being offered for information in the case is more than $40,000.