Sao Paolo lived up to its reputation as the most dangerous stop on the Formula One calendar as Friday's free practice sessions were overshadowed by a spate of gun-related crimes.

A number of teams have been victimised over the past two days, but Williams were the first to suffer, leading them to request that the FIA call on local officials to beef up security around the circuit after a team vehicle was apparently shot at on its way to the circuit.

Jaguar, too, suffered, with eight computers stolen from support vehicles. European Minardi were doubly struck, first as the Anglo-Italian outfit's team manager was robbed at gunpoint by three men as he left a city bank, and then with the theft of a number of front wheels from the circuit.

Most sinister, however, were the unconfirmed reports surfacing yesterday which suggested that two local race officials were shot and killed on Thursday night. An FIA spokesperson was unable to establish the veracity of the reports late yesterday afternoon.

Sao Paolo has had a troubled past with F1. Long regarded as the season's most dangerous stop, the circuit also received a stern rebuke from the FIA last year over the poor state of the track, and also after several advertising hoardings fell onto the track during qualifying. Whether this weekend's events will affect the city's future on the F1 calendar remains to be seen.

The number and severity of the crimes cast a pall over yesterday's free practice sessions in which David Coulthard topped the timesheets, over a second clear of the rest of the field. Jarno Trulli, though, gave Eddie Jordan the perfect 52nd birthday present with a strong performance to finish second. Team-mate Heinz Harald Frentzen was forced to stop on track with suspected alternator problems.

"Basically the car was good in the first session," said Trulli. "But we worked hard on the set-up and managed to take a few seconds off my lap time when we went out again. It was a positive practice for me, although we did lose some time in the second session after a small problem with the brakes. The car look competitive and I'm confident for tomorrow."

Coulthard's time comes as a welcome boost for McLaren, who have suffered badly at the hands of a rampant Ferrari team in the first two races of the season. Coulthard admitted that the time was pleasing but warned that qualifying would not be as easy.

"I'm pleasantly surprised with the progress made with the car since the last race," said Coulthard. "I don't know whether it's enough, but we I do believe we'll be closer to Ferrari this weekend."

Close may not earn Coulthard a celebratory cigar, however, a fact confirmed by the presence of Michael Schumacher in third place. The world champion has established a comfortable 10-point lead over his nearest rivals, team-mate Rubens Barrichello and Coulthard, and yesterday said that he was comfortable with the progress he was making here, despite suffering a puncture.

"This is a difficult circuit, but I'm pretty happy with the work I've done so far," said Schumacher. "The car's not a hundred per cent, but we have made some progress and we'll continue that work tomorrow. Looking at the time it seems the opposition is a bit closer than the last two races, but you can't really tell on Friday, you can never be sure of what fuel loads or tyres people were running."

McLaren's task is made all the more daunting by a look at Schumacher's record at Interlagos. The German has won three of the last six races here, taking back-toback victories in 1994 and 1995 and racing to a facile win last year as he set about establishing a massive lead to take back to the European leg of the season.

With Ferrari enjoying a period of total dominance, betting against the German going to Imola in two weeks with a similarly comfortable cushion would appear foolhardy.