The worst multiple murder in recent Philadelphia history happened in their offices.

Their president and founder were killed in their conference room, along with a brother and a friend. Their manager of human resources was shot in the stomach and is gradually winning the fight for his life.

Now Zigzag Net Inc.'s senior officers are fighting for the life of their company, a small Web design and marketing firm.

"The odds are that in most of these cases, the small business doesn't survive," said lawyer Jeffrey Pasek, a partner in Cozen O'Connor, of Philadelphia. "The exception is when there is a partner who can step in and take over the business."

On Wednesday, still reeling from the shock of the Monday night slayings, Zigzag's vice president for marketing and business development began to call the agency's clients to assure them that Zigzag would continue, despite the death of founder Mark Norris. "That's what we know Mark would do," said Glenda Laudisio.

She is making the right moves, said Louis Applebaum. He found himself in a somewhat similar situation 25 years ago, when, as No. 2 man at A. Pomerantz & Co., he had to take over after the sudden death of the company's president, Lester Pomerantz.

Pomerantz and his wife, Joan, died in 1982 when their rented car struck a truck along a coastal road in what was then Yugoslavia. Pomerantz, then 64, had been president and chief executive officer of the Philadelphia-based office furniture and supply distributor and retailer that had never been run by anyone other than the family.

That night, with the Pomerantz family's blessing, Applebaum took over, working through shock and sadness to save the business and the jobs of hundreds of employees.

Applebaum started by meeting with employees to reassure them that the firm would continue. He communicated the same message to far-flung offices. Then he reached out to the business' suppliers and customers.

"You have to speak to your major customers and assure them that it is business as usual and that they should be calm, cool and collected," he said. "The key to survival is the level [of expertise] of the management," he said.

In Zigzag's case, Vasantha Dammavalam is a vice president of technology and poised to run the company, Laudisio said.

But Dammavalam lives in New York City and will have to overcome his own nightmares.

The gunman, shooter Vincent Dortch, planned to drive to New York that night to kill him, but was dissuaded, police said. Dammavalam is also the main surviving partner in the Upstate New York land deal that led to the shooting.

Meanwhile, Zigzag faces serious financial obstacles, including a federal tax lien for as much as $179,562 and thousands of dollars owed to the state's unemployment compensation fund.

However, it can draw on an impressive list of clients and boast of prizewinning work, including a campaign to urge at-risk young people to be tested for HIV-AIDS.

The first step is to cope with the psychological trauma of the employees, said Lyle Labardee, chief executive of the Michigan-based Crisis Care Management Network, a group of specialists who are called in to handle situations of workplace violence.

"People have encountered horrific sights and sounds that are not easily forgotten," he said.

In a larger company, counselors will set up sessions with employees, divided into groups depending on how much they have seen and heard, he said.

Meanwhile, on the practical side, cleaners need to be called in to what becomes a biohazard situation, Labardee said. Then, contractors have to make repairs. "If there are bullet holes, you might want to put up new drywall," he said.

"The potential for that entity to continue on will depend on the resiliency of the individuals who remain on the organization," Labardee said.

After Peter Amico, the president, chief executive and chairman of Airtrax Inc., died suddenly in August, the Blackwood, N.J., company's share price began to fall, and there were rumors that it would close.

"It was a transitional time in a public company, and investors don't like uncertainty," said the new chairman, Andrew Guzzetti.

Even though the company, which designs forklifts, was small - about a dozen on staff like Zigzag - it was publicly traded. It could lean on its board of directors.

Sadly, almost by rote, the board took the steps necessary to fulfill its legal, fiduciary obligations. Those obligations became a steadying bulwark.

Guzzetti became the chairman within a few days of Amico's death. He had been a financial and management consultant and board member.

Guzzetti said Airtrax quickly moved to reassure its employees, particularly its key engineering staff. One of them - a longtime colleague of Amico's - was immediately made acting chief executive. "He knew the nuts and bolts of the business," Guzzetti said.

In the months that followed, Guzzetti said, Airtrax realized that it needed a strong marketing and sales-oriented person at the top to compensate for Amico's entrepreneurial fervor.

In October, Airtrax named Robert Watson, an executive with marketing and management experience, to become chief executive. Nicholas Fenelli, the engineer who stepped in as CEO after Amico's death, became chief operating officer.

Guzzetti said that, ultimately, the leaders of Zigzag needed to take a hard look at their business, to see what strengths and weaknesses the company now had after the tragedy and adjust accordingly.

In a statement posted on its Web site Thursday, Zigzag said it was now looking for temporary or satellite space to resume daily operations.

"At this point in time, our priority is the well-being of the families of our lost friends, wounded colleague and staff," the Web statement said.

"Our next and immediate priority is our relationship with our clients, partners and vendors. Zigzag's business is and will continue to be very strong, and the company, management and staff will take the necessary step to keep the business operating smoothly."

Laudisio said she was determined to press ahead. "I plan to do what I can do to carry on his legacy."

Contact staff writer Jane M. Von Bergen at 215-854-2769 or jvonbergen@phillynews.com.

Staff writer Andrew Maykuth contributed to this report.