By Charlotte Parsons BBC News Online

Maryland residents were jittery but defiant after the apparently random shooting spree in which six people have been shot dead and another hospitalised.

Employers and schools have issued warnings to staff and students, as police hunt two men spotted fleeing one of the slaying scenes in a white van.

A seventh person has been shot

You can't even walk down the street without looking over your shoulder

Dexter Evans

Law student Mako Sasaki said she has already received two separate e-mails warning her about the attacks - one from the dean of her law school, and another from the trade association where she works as an intern.

But although she has begun looking over her shoulder, Ms Sasaki told BBC News Online that she refuses to let the shootings change her life.

"When I go out I check - if there's a white van with two people in it, I look," said the 25-year-old, whose Bethesda home is 10 minutes from one of the murder scenes.

"But I wouldn't stop going out."

Extra caution

Her neighbours echoed that sentiment.

"I had to shop. I need to eat. I can't stay at home all day," said Kira Leonova, who works at a bookstore near one of the shooting scenes.

"I have to work and I have a family."

Dexter Evans, 20, said he now looks twice at every white truck.

"You can't even walk down the street without looking over your shoulder," he said.

Extra police are patrolling the streets and emergency services have been inundated with calls from people reporting suspicious noises.

Public executions

All the victims were gunned down in public places in broad daylight.

Police believe the attacks are linked, but are struggling to find a connection between them.

This area is supposed to be safe

Mako Sasaki

One victim was shot dead while riding a lawnmower, another while cleaning her car at a petrol station.

None of the seven appeared to have been robbed.

Police also said race did not seem to be a motive. The victims were white, black, Hispanic and a man from India.

The shootings took place in one of the country's wealthiest counties.

"This area is supposed to be safe," Ms Sasaki said.