By Alexandra Ulmer and Diego Oré

VALENCIA/CARACAS (Reuters) - When a man they believed to be a thief sneaked into their parking lot in the Venezuelan city of Valencia, angry residents caught him, stripped him and beat him with fists, sticks and stones.

They tied him up and doused him in gasoline, according to witnesses, in one of what rights groups and media reports say are an increasing number of mob beatings and lynchings in a country ravaged by crime.

That August night, as locals say is common, three people had sneaked into Valencia's Kerdell residential block. In past such break-ins, thieves have made off with car tires, batteries and radios.

But this time, one resident spotted the trespassers and alerted other neighbors, according to the witnesses.

"'Kill him, give it to him,' they shouted," recounted Trina Castro, 82, in this once middle-class and peaceful area that is now plagued with garbage and graffiti. One reads: "Get ready, thief, here we burn you. Regards, Kerdell."

"I tried to stop the mob but the level of violence endangered anyone who opposed them," said another witness, asking to remain anonymous for fear of retaliation.

The unconscious man, who was not torched, was evacuated and is now in the local hospital's trauma ward, according to witnesses and Valencia's police. The police said they had no further details and did not identify the man.

A source at the Interior Ministry, who asked to remain anonymous because the minister is the only person authorized to speak on the record, said it does not usually comment on cases under investigation. Venezuela's state prosecutor's office said it had not issued a statement on the incident.

The Venezuelan Observatory of Violence (OVV), a non-governmental organization, estimates there were 40 cases in 2014 of lynchings, usually defined as extrajudicial killings by mobs.

The Observatory does not yet have figures for 2015, but a Reuters tally of media reports shows that in the last month alone there have been over a dozen mob-led beatings or lynchings.

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There is no official public data on mob justice in once industry-rich Valencia or across a country that is in economic crisis. President Nicolas Maduro's administration often blames violence on political rivals seeking to sabotage the socialist government. Authorities have also accused foreign media of exaggerating crime in Venezuela.

'COLLECTIVE CATHARSIS'

The OVV and other rights groups say mob justice is rising as a response to perceived helplessness in the face of crime.

"Lynching is a collective catharsis. Everyone is guilty and no one is guilty," said Roberto Briceno of the OVV.

Venezuela has the world's second highest homicide rate, at 53.7 per 100,000 people in 2012, according to the United Nations, and weapons are easily available.

Courts are slow, judges are sometimes on the take and criminals are frequently released right after arrest, according to non-profit groups.

"The police can arrest criminals, but then the courts free them. As long as there's no response from the state, lynchings will increase," said Elisio Guzman, the head of state police in the state of Miranda.

Venezuela, a major oil exporter, is also mired in a deep economic crisis, hurt by currency controls and falling oil prices.

The International Monetary Fund expects a contraction of 7 percent to the economy this year and private economists calculate annual inflation has topped 100 percent. Shortages fuel a lucrative black market for car batteries and food, increasing incentives for theft.

'HIT THEM HARD'

While lynchings used to be primarily in low-income areas and in response to murders or rapes, monitoring groups say, there have been attacks recently in wealthier areas on common thieves.

Last month, two men were chased and badly beaten for stealing a purse in Caracas' affluent Los Palos Grandes neighborhood. Residents shouted "hit them hard" from their windows before police arrived and stopped the thrashing, witnesses said.

"The thieves are always after us. I don't agree with lynchings, but what other options do we have?" said witness Raquel Brito, 54.

A 20 year-old died in a middle-class area of Caracas in August after being punched, shot and burned for suspected robbery, media reported. Reuters could not independently confirm the case.

In Valencia, the Kerdell complex sits a block from a branch of the country's CICPC investigative police. But some residents here, as in much of Venezuela, say they tend to view security forces as overworked and corrupt.

Officers, in turn, frequently complain of poor pay and equipment.

Some Venezuelans are deeply shocked by the mob justice. Others fear violent citizens' response to crime will only breed more violence.

"Now we're all scared that retaliation could be in store," said retired mathematics and physics teacher Maria Perez, 66, who has lived in Kerdell for 30 years but is now thinking of moving out.

(Additional reporting by Dorys Lopez in Valencia and Mircely Guanipa in Punto Fijo; Writing by Alexandra Ulmer; Editing by Andrew Cawthorne and Frances Kerry)