Animal rights campaigners arrested after taking part in demonstrations say they will sue police.
Margaret Bardsley and her daughter Lindsey were arrested at their homes in Preston, near Hedon, in raids earlier this year.
They were taken into custody in connection with threats to and intimidation of suppliers to B &K Universal Ltd, based at Aldbrough, near Hornsea, which supplies animals for testing at laboratories.
However, neither of them were charged with any offence and they say they were wrongfully arrested and will sue Humberside Police.
Margaret, 57, said: "We are not extremists and have never been involved in any criminal activity.
"We are there to highlight what happens in the vivisection industry, which we believe is wrong.
"Throughout our protests, we have never sought to close the site down. We want the company to diversify and not use animals. We do not want to see people lose their jobs.
"We have never been given a proper explanation as to why we were arrested and are going to sue the police for wrongful arrest."
The two women were arrested with a 17-year-old man, of Leeds, and a 27-year-old, of Shipley, on February 20.
At the time they were taken into custody, police said the intimidation was in the form of e-mails, telephone calls and faxes.
A number of items were seized during their arrests, including computers, photographs and mobile phones.
They have since been returned but both women believe there are some items missing.
Both campaigners believe they are the victims of police harassment.
Margaret said: "Usually we attend the site with two other ladies in their 60s.
"We do not pose a threat, but sometimes there are three or four police officers to each of us."
The women were taken into custody at 7am and Margaret was released at 8pm and Lindsey at 6.30pm.
Lindsey said: "It felt like an eternity and was like hell on earth.
"It was scary and degrading. But we will not give up and we are determined to continue with our protests."
Lisa Fleming, of Humberside Police, confirmed both women had been arrested.
She said: "After consultation with the Crown Prosecution Service, it was determined there was insufficient evidence to pursue the matter further and this decision has been communicated to the women involved.
"However, no complaint has been received in relation to the arrests."