Moscow Mayor Yuri Luzhkov said prosecutors have opened a criminal investigation and that the city administration has established a commission to look into the technical aspects of the case.
Muscovites, jittery after a recent bombing on the city's subway, initially feared a terrorist attack. But authorities quickly ruled out an explosion, suggesting the collapse was likely caused by the weight of snow piled on the glass roof.
Pavel Kleimovskii, a spokesman for the Moscow department of Russia's Interior Ministry, initially offered that hypothesis to the press. Other officials pointed at various other possibilities, including problems in the design, construction, and maintenance of the structure.
Luzhkov says samples of the materials used to build the water park have been collected for testing and that all possibilities need to be examined.
"I would not concentrate on one of the versions,” he said. “The commission is now to begin its investigation. I would be extremely cautious in determining someone's fault in the mass media right now that could [later prove] erroneous."
Meanwhile, city authorities have suspended the licenses of two companies involved in the design and construction of the water park -- Russian architect Sergey Kisselev and Partners and the Turkish builder Kocak Insaat. The $30 million water park opened in 2002 to critical acclaim from the city government. It was bought by a Russian company called Terra Oil late last year from the previous owner, European Technologies and Services, also a Russian firm.
Russian President Vladimir Putin today demanded punishment for those responsible for the collapse.
Moscow's deputy chief prosecutor Vladimir Yudin said today that documents have been seized to aid in the probe.
"Today, we are finishing seizing documents from all the companies involved -- contractors, owners, constructors. The documents will be studied during the investigation and the forensic inquiry," Yudin said.
The head of Russia's Construction and Housing Committee, Nikolai Koshman, says the tragedy may force the implementation of even tougher construction standards.
"Now, in view of this tragic incident, we are going to toughen our requirements to construction projects, surveying organizations that receive construction licenses, and we will pay special attention to the practical implementation of those projects," Koshman said.
Moscow authorities have ordered check-ups on all sports and public facilities with construction similar to that of the water park.
Andrei Gozak is a Moscow architect. He says the design and construction of the water park complex will be the easiest to investigate due to the documentation and necessary quality tests required by law.
"To check on construction elements and the compliance of the concrete and steel used in them against the norms will be very easy. To check the design and engineering ideas and calculations will also be easy. The most difficult will be the examination of the third vital stage -- the building's maintenance," Gozak said.
Gozak describes construction laws in Russia as strict and says many tests are required before a design is approved and sent to a building firm.
"All three stages [design, construction, and maintenance] are required by law to respond to the most extreme conditions -- the hardest wind, the heaviest snowfall, displacements of stressed when snow is accumulated on only one part of the cupola, and extreme side winds, as well. All of that should be taken into account and calculated with a tenfold reserve. There could only be a disaster if the law was violated," Gozak said.
Experts say the construction of such indoor swimming parks presents difficult technical and scientific problems. The humid climate inside the structure -- combined with the chemicals used for water purification and the extreme climate changes outside -- can cause metal corrosion, as well as cracks in concrete.
Gozak says these problems mean a lot of attention must be paid to the proper maintenance of such facilities.
"If during two years of the building use, vapor, temperature, and moisture could have reached the metal [reinforcement] grid [in the concrete elements], that could have been one of the reasons of the accident. The maintenance team bears responsibility here because they are supposed to watch the structure's work and periodically check its integrity and water-proofing," Gozak said.
Both companies involved in the construction of the water park are well-known in Russia.
Sergey Kisselev and Partners has designed dozens of buildings throughout the country, including residential, office, and commercial spaces. The company has worked on a number of high-profile projects, including the reconstruction of the Russian president's office.
The Turkish Kocak Insaat construction company has been in business in Russia for 15 years and also has worked on a number of significant projects. The company has been ordered to stop work at several sites around Russia pending the outcome of the investigation.
Both companies have declined to comment on the tragedy, pending the results of the investigation. But Kocak Insaat initially expressed shock in reaction to the news.