Fur flies as Washington's finest track down victims of the Zoogate scandal

Memos are leaked, officials stonewall and accusations fly about a cover-up. Finally, Congress holds hearings and orders a major investigation. Yes, another classic Washington scandal is unfolding – but not in the corridors of human power.

This one involves some very strange happenings in the natural world or, more to the point, at the National Zoo.

Not to put too fine a point on it, the animals on display in this pleasant piece of real estate in north-west Washington have been dropping like flies ever since the veterinarian Lucy Spelman was named director of the zoo in June 2000.

Over the past couple of years, the list of victims includes some of the animal kingdom's VIPs – most lately two red pandas and a pygmy hippopotamus, both on the endangered species list. Among other creatures that have died or but been put down in peculiar circumstances are three zebras, two giraffes, a lion and a bobcat.

At first, the strange events went unnoticed except by experts. They were what the late Ron Ziegler, spokesman for Richard Nixon, might have called "third-rate accidents". But with the death of the two red pandas on 11 January, the sequence of disasters could no longer be hushed up.

The unfortunate animals, it transpired, perished after a contractor put poisonous aluminium phosphide pellets inside the pen, part of an attempt to control the zoo's rat population.

Ms Spelman's staff seemed to be stalling, saying it would be weeks before a result would be known. And for the newspaper that cracked Watergate, such behaviour was like a red rag to a bull. The Washington Post invoked the Freedom of Information Act to get hold of the panda autopsies – only for its request to be denied, perhaps on the grounds of panda privacy rights.

But a flood of other embarrassing facts soon emerged. Tana, the African lion, died after being left alone for a night after having surgery.

A bobcat that was put to sleep for a limp, the Post found, was later found to have an ingrown claw.

As for the zebras, they simply starved to death after their daily feed was reduced during a spell of particularly cold weather.

The death of the pygmy hippo remains a mystery.

Then the newspaper came up with a US Department of Agriculture internal report listing a series of zoo violations of the Animal Welfare Act, while The Washingtonian magazine claimed there was a serious morale problem at the zoo, amid a lack of confidence by the staff in Ms Spelman.

Those reports, inevitably, were noticed on Capitol Hill. The House Adminstration Committee called a hearing, and decided to ask the National Academy of Sciences to take a closer look at the zoo's operations.

"The clouds surrounding this important institution must be lifted," the panel's chairman, the Ohio Republican Bob Ney, solemnly declared.

This statement, when translated into the language of Watergate means, "What did Ms Spelman know, and when did she know it?"

It would all be hilarious if it weren't so sad. Sad for the animals, of course – though the embattled zoo director insists that most of the demises could be put down to frailty and old age. But sad for us too.

The zoo had always been an escape from the political rat race in the city which surrounds it. No longer. The rat race, or rather rat poison, has reached it as well.