A Knightscope K5 security robot named 'Steve' fell down some stairs into a water feature at an office complex in Washington DC, USA. 

Knightscope officials later said that this was an 'isolated incident' and that Steve had slipped on a 'loose brick surface' before tipping down the stairs into the water. 

The company added that the incident had been caused by an error in the self-driving algorithm, and that a new robot would be delivered to Washington Harbour for free.

The K5 is equipped with sensors, a 360-degree video camera, microphones, air quality sensors, and thermal imaging capabilities. 

According to Knightscope it can scan up to 1,500 car number plates per minute and detect gun shots and other notable sounds.