By Amy Silverman
By Olivia LaVecchia
By Monica Alonzo and Stephen Lemons
By Chris Parker
By Michael Lacey
By Weston Phippen
Ed Posada Sr. kneels in the desert a mile from the Mexican border. He knows every inch of this landscape off Geronimo Trail Road, a few minutes east of Douglas.
"This is where that bastard shot my son in the face, tu entendes?" he says, flashing the mad grin of the haunted. "Eddie was easy meat, unarmed, drunk on his ass.
"Then the guy went over to Sergio's car--it was there--and shot him like he was a dog. Then he went home and put on his badge. Cold-blooded.
"Thirteen months earlier, on August 8, 1994, Posada had knelt in the same spot, trying to make sense of what had happened there. A friend videotaped him as he inspected the crime scene, which Cochise County sheriff's detectives had examined hours earlier.
The videotape is chilling. It shows Posada poking a stick into soil soaked with the blood of his first-born. He says he was looking for clues. All he found were maggots.
His name is Mark Martinez, a U.S. Border Patrol agent based in Douglas. Martinez was the last known person to have seen the two men alive--at the murder site in the early hours of Friday, August 5, 1994.
There was no known motive for the murders. But when word got around, as it does in this city of 14,000, everyone suspected a drug connection. Experts compare porous border towns such as Douglas to mini-Miamis of the early 1980s.
The frontier mentality is palpable in Douglas, home to the infamous drug tunnel, center stripe of a thoroughfare dubbed Cocaine Alley.
Drugs move north, stolen vehicles move south. The cash smugglers can tempt government agents with is incalculable. It's a place where the differences between good and bad guys blur, and the arrests of bad cops surprise nobody. Just this month, a veteran Border Patrol agent was busted for his alleged involvement in smuggling 1,200 pounds of cocaine.
"You know Douglas," Martinez's girlfriend, Nicole Foster, told homicide investigators. "You're gonna have to stay at home if you don't want to talk to someone who's dealing in drugs.
"Posada and Tapia, both in their early 20s, had been known to dabble in dope, though the extent of their involvement at the time of their deaths is speculative.
Martinez, then 30, had no known link to drug smuggling. But he became the chief suspect soon after some teenagers found the three-day-old remains of the two men.
When sheriff's detectives surprised Martinez at his home in the wee hours of August 8 for an interview, they found his account fraught with inconsistencies.
For example, a skittish Martinez first denied owning weapons other than his agency-issued .357. He then admitted to having possessed a shotgun and a .22 handgun. Pressed further, he said he currently owned a Smith & Wesson 9mm, and that it was in his Chevy pickup.
At that point, the detectives weren't aware that Posada and Tapia had been killed by a 9mm. But they didn't ask Martinez to produce the gun, even after his furtive answers had raised suspicions.
Their failure to do so would loom large.
Martinez confirmed what the investigators had been told by others: that he'd been alone with the two victims at the murder scene after everyone else had left a party there.
But Martinez claimed that two unidentified Mexican men had stopped by the desert site in a pickup, not long before he'd left about 4 a.m.
Investigators soon discovered that he had behaved erratically in the hours after leaving the party site.
Shortly after the sun rose, Martinez made an eventful 50-mile trip to Sierra Vista. He took a roundabout route along a dirt road, and wound up driving into a barbed-wire fence. When a passerby stopped, he refused any assistance.
In Sierra Vista, the agent bought a change of clothes and may have disposed of the ones he'd been wearing. He paid for a night's lodging at a Sierra Vista hotel. But he returned to Douglas a few hours later.
A police search of Martinez's home, vehicle and work locker later turned up an estimated 5,000 rounds of 9mm ammunition, but no 9mm gun.
A day after detectives searched his home, Martinez hired Michael Piccarreta to represent him. The Tucson attorney is renowned for his effective criminal defenses of accused border cops.
Piccarreta suggested to Cochise County authorities that Martinez might identify "the true killers"--provided his client was promised immunity from prosecution. The attorney told the authorities that he feared for Martinez's life.
"We have heard from various sources," Piccarreta wrote sheriff's detectives two weeks after the murders, "that both Mr. Tapia and Mr. Posada and his father, Ed Posada, were actively involved in large-scale narcotics activity. We are all aware that violence and death are risks associated with the narcotics business.
"The dead men were no choirboys. But proof of "large-scale narcotics activity" didn't exist. And even if it did, Martinez's tale of the two mystery men--like the "shaggy-haired stranger" of true-crime lore--seemed dubious.
Authorities didn't respond to Piccarreta's offer.
Mark Martinez remains the one and only murder suspect. Many folks in Cochise County--including the case detectives, some of Martinez's peers in the Border Patrol and the victims' families--don't consider the murders to be mysterious.