Garland Price has been a police officer for 13 years, and in that time he has learned to rely on his instincts about the guilt or innocence of suspects. And to Price, although Joseph (Jody) Cady was no angel, it just didn't figure that Cady was guilty of the latest crime with which he had been charged.

Even though two witnesses to the robbery of an Oxon Hill grocery had picked Cady's picture from a spread of six photographs, the open-and-shut case that the Prince George's County prosecutor's office thought it had wouldn't close in the detective's mind.

"I could have put this case on a back burner and waited for the trial, but deep down inside I believed him," said Price, who has worked on the robbery squad in southern Prince George's the last eight years. "It was just a gut feeling, but you come across a lot of people . . . . "

Price said Cady "came in and swore on his babies . . . " that he was innocent, and, while that isn't unusual for suspects, some of Price's colleagues who had dealt with Cady said that he had admitted guilt after previous arrests.

But the odds, and the facts, seemed stacked against the 27-year-old Cady, who had a string of convictions. In addition to the eyewitness identifications, a young, white male had been the prime suspect in a series of robberies in the Oxon Hill area, and, when Cady was taken into custody, the robberies stopped.

Even Cady's public-defender, Alan Drew, was not sanguine about his client's prospects: "Based on the evidence that I had, without Detective Price doing what he did, there was a chance that Mr. Cady would have been found guilty of robbery. He had an alibi defense, but it was pretty shaky."

And Cady's acquaintances didn't help his cause. A former classmate recalled Cady as "the kind of guy you wouldn't turn your back on, beause he might throw a brick at you." And a neighbor from the Southlawn housing development in Oxon Hill said, "He'd rob you in a minute."

Worst of all, John Boyer, who was working behind the counter at the Fort Foote Market when the robbery occurred March 15, 1981, said he had known Cady as a youth.

When he picked Cady's picture from among the photographs that police showed to him and another store clerk, Boyer said he thought there was something familiar about the customer who dropped a $5 bill and a six-pack of beer on the counter, and said, "Don't move, everything will be okay."

That identification, in which the other clerk concurred, was more than enough to bring Cady in on a charge of armed robbery.

But Price wasn't convinced. For one thing, Cady didn't have a car--the robber drove off in a green Oldsmobile--although he could have borrowed or stolen one for the robbery. Also, he was a dedicated Budweiser drinker, and the robber bought Michelob. And the jail-wise Cady volunteered to take a lie detector test and even waived his right to have a lawyer present when Price interviewed him.

But mostly, it was "that gut feeling" that Price, 35, had developed during his experience as a policeman, first in D.C., and more recently in Prince George's.

The big break came about two weeks after Cady was released on $5,000 bond, when a man fitting Cady's description--a young, white man with brown hair and a small stud earring in his right lobe--robbed a bank across the Potomac in Springfield.

A Fairfax County police investigator, T. R. Miles, investigating the bank job, showed Price a picture of the suspect because the man's sister lived in Oxon Hill.

Price quickly guessed that the suspect, Peter Bennet Reeves, 22, might be the person who also held up the Fort Foote store. So Price went to the home of Reeves' sister, Melody Walton, and showed her a photograph of Cady. "I was struck by the resemblance" to her brother, Walton said.

She went on to say that her brother, who had escaped from California authorities two weeks before the Oxon Hill robbery, had been in the area and even had borrowed her pale green Oldsmobile the day the market was held up.

By the time Price got this information, Reeves had been taken into custody in Tennessee, for robbing a convenience store.

Walton, an administrative assistant with a legal aid association, said "Garland Price had a feeling and I did, too, that my brother had done it, so I wrote to him. I love my brother with all my heart, but he didn't deal with his life realistically. I didn't feel guilty about it because I didn't want to see someone else affected by what he did."

Her brother wrote back that, "I don't know if I robbed the Fort Foote market or not, but I did rob a small market on the 15th or 16th. I think it was near your pad."

That was enough for Price, who initiated an extradition proceeding. When Reeves arrived here, he went to his sister's house with the detective, and from there he directed Price to the market and described the employes and his actions, right down to the Michelob.

That testimony was enough to get William Hale, the assistant state's attorney, to dismiss the charge against Cady. Because Reeves already faces 30 years in prison--21 in Tennessee and nine in California--Hale said he doubts that he'll ever be brought to trial on the Oxon Hill robbery.

"Garland Price really did a good job on this," the prosecutor said. "He really went the extra mile for Cady. He's a good detective."

Price is pleased. "This is probably the most rewarding case I've ever worked." the detective said. "Not only did I find the right person, but I cleared an innocent man."

Reeves, interviewed by telephone from prison in Nashville, said, "I sure hope Cady is doing something, and not letting it [the opportunity] go to waste. That would burn me up."

Price said Cady, along with his wife and three children, checked out of a motel in Alexandria recently, where they had been living since he was cleared last December, and hasn't been heard of since.